C ABI: full example suite + docs & About coverage (#224)

Stacked on #222 (base `feat/c-abi-hub`), so the diff is just the additions on top of the hub foundation — no merge of #222 required.

## What this adds

**Examples — full parity with rust/python/node (`examples/c/`)**
- `streaming.c` upgraded to the multi-indicator (SMA/EMA/RSI/MACD + signals) demo
- `backtest.c`, `multi_timeframe.c` (manual time-bucket resampling), `parallel_assets.c` (serial vs OpenMP fan-out, one handle per asset)
- three educational strategies: `strategy_rsi_mean_reversion.c`, `strategy_macd_adx.c`, `strategy_bollinger_squeeze.c`
- two network examples shelling out to `curl`: `fetch_btcusdt.c`, `live_binance.c` (REST poll)
- two header-only helpers (`wickra_csv.h`, `wickra_strategy.h`) since the C ABI ships no IO layer
- CMake builds all 11; the 9 offline ones run under `ctest` on 3 OS; the network two are built-only

**Docs & metadata — surface the C ABI everywhere it was missing**
- ARCHITECTURE diagram + crate table, SECURITY + THREAT_MODEL (the C ABI as the sole `unsafe` FFI surface), the three binding package READMEs, issue/PR templates, CHANGELOG, and the GitHub About template (live About + org description updated too)

**Cleanup**
- removed all references to the private generator tooling from public files (`bindings/c/src/lib.rs` header, `CONTRIBUTING.md`, `sync-about.yml`)

Verified locally: `cargo build -p wickra-c --release`, `cmake + ctest` (9/9 pass), and `-Wall -Wextra -Wpedantic` clean on gcc 13.

.github/ISSUE_TEMPLATE/bug_report.md

@@ -30,7 +30,7 @@ assignees: ""
 ## Environment
 
 - Wickra version:
-- Language / binding: <!-- Rust crate / Python / Node / WASM -->
+- Language / binding: <!-- Rust crate / Python / Node / WASM / C ABI -->
 - OS and architecture:
 - Rust / Python / Node version (If relevant):
 

.github/ISSUE_TEMPLATE/performance_regression.md

@@ -13,7 +13,7 @@ assignees: []
 ## Affected code path
 
 - Indicator / API: `e.g. EMA.update`
-- Binding: `Rust / Python / Node / Wasm`
+- Binding: `Rust / Python / Node / Wasm / C ABI`
 - Hot loop or one-shot call?
 
 ## Versions compared

.github/ISSUE_TEMPLATE/question.md

@@ -33,4 +33,4 @@ import wickra as ta
 ## Environment (Only if relevant)
 
 - Wickra version: `e.g. 0.4.2`
-- Binding: `Rust / Python / Node / Wasm`
+- Binding: `Rust / Python / Node / Wasm / C ABI`

.github/PULL_REQUEST_TEMPLATE.md

@@ -22,7 +22,7 @@
 - [ ] `cargo clippy --workspace --all-targets -- -D warnings` is clean.
 - [ ] `cargo test --workspace` passes.
 - [ ] New behaviour has tests; bug fixes have a regression test.
-- [ ] Public API changes are mirrored in the Python / Node / WASM bindings
+- [ ] Public API changes are mirrored in the Python / Node / WASM bindings and the C ABI is regenerated
       and their type stubs (If applicable).
 - [ ] The relevant page on the [documentation site](https://docs.wickra.org)
       and the `README.md` are updated (If applicable). Docs edits go to a

.github/workflows/sync-about.yml

@@ -42,10 +42,10 @@ name: Sync indicator count
 # single source of truth for what the bindings reach.
 #
 # Design: on PRs this workflow is a READ-ONLY check. The indicator wiring
-# (ScriptHelpers/_common.py wire_readme_counter) bumps both README.md and
+# bumps both README.md and docs/README.md inside the author's code commit, so
-# docs/README.md inside the author's code commit, so the counter is already
+# the counter is already correct by the time CI runs. If it is not, the check
-# correct by the time CI runs. If it is not, the check below fails loud and
+# below fails loud and asks the author to re-run the wiring — it never pushes a
-# asks the author to re-run the wiring — it never pushes a fix-up commit.
+# fix-up commit.
 #
 # (An earlier version pushed a GITHUB_TOKEN "sync indicator count" commit to
 # the PR head. Because GITHUB_TOKEN pushes trigger no workflows, that commit
@@ -149,7 +149,7 @@ jobs:
           # actually live (Cloudflare Pages, P8.1); merging this PR is therefore
           # gated on the domain resolving, otherwise the About link would 404.
           homepage="https://docs.wickra.org"
-          desc="Streaming-first technical indicators with a Rust core and Python, Node.js, and WebAssembly bindings. ${n} indicators, O(1) per-tick updates, no system dependencies. Drop-in TA-Lib replacement."
+          desc="Streaming-first technical indicators with a Rust core and Python, Node.js, WebAssembly, and C ABI bindings. ${n} indicators, O(1) per-tick updates, no system dependencies. Drop-in TA-Lib replacement."
           # Enforce the homepage unconditionally — it is a constant, so this both
           # corrects the stale kingchenc URL and self-heals any future drift.
           # Same Administration-write permission as --description (no extra scope).

ARCHITECTURE.md

@@ -29,14 +29,20 @@ or replace lives behind a separate crate boundary.
                 ▲
                 │ (every binding wraps the same core)
                 │
-   ┌────────────┴───────────┬─────────────────────┐
+   ┌───────────┬────────────┴┬──────────────┬──────────────────────┐
-   │                        │                     │
+   │           │             │              │                      │
-┌──▼──────┐         ┌───────▼──────┐      ┌───────▼────────┐
+┌──▼─────┐ ┌───▼────┐ ┌──────▼──────┐ ┌─────▼──────────────┐
-│ Python  │         │     Node     │      │     WASM       │
+│ Python │ │  Node  │ │    WASM     │ │  C ABI (cbindgen)  │
-│ (PyO3)  │         │ (napi-rs)    │      │ (wasm-bindgen) │
+│ (PyO3) │ │(napi-rs)│ │(wasm-bindgen)│ │  cdylib + header   │
-└─────────┘         └──────────────┘      └────────────────┘
+└────────┘ └────────┘ └─────────────┘ └────────────────────┘
 ```
 
+Python, Node and WASM are *native* Rust bindings (PyO3 / napi-rs /
+wasm-bindgen). The C ABI is the *hub* every other C-capable language links
+against: it builds to a `cdylib`/`staticlib` plus a generated `wickra.h`, and
+C / C++ / Go / C# / Java / R consume that one artifact rather than each
+re-wrapping the core.
+
 | Crate | Path | What it owns | Public deps |
 |---|---|---|---|
 | `wickra-core` | `crates/wickra-core` | every indicator, the `Indicator` trait, `BatchExt`, `Candle`/`Tick` types, `Error` | `thiserror`, `rayon` (parallel batch) |
@@ -45,6 +51,7 @@ or replace lives behind a separate crate boundary.
 | `wickra-python` | `bindings/python` | `_wickra` PyO3 module + Python package | `pyo3`, `numpy`, depends on `wickra-core` |
 | `wickra-node` | `bindings/node` | NAPI-RS native binding | `napi`, depends on `wickra-core` |
 | `wickra-wasm` | `bindings/wasm` | WebAssembly binding | `wasm-bindgen`, depends on `wickra-core` |
+| `wickra-c` | `bindings/c` | C ABI hub — `cdylib`/`staticlib` + generated `wickra.h` (cbindgen) | depends on `wickra-core` |
 | `wickra-examples` | `examples/rust` | runnable binary examples | depends on `wickra`, `wickra-data` |
 
 The `fuzz/` directory is **excluded** from the workspace (it has its own

CHANGELOG.md

@@ -10,8 +10,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **C ABI (`bindings/c`)** — a `cdylib` + `staticlib` plus a generated
   `include/wickra.h` exposing all 514 indicators and 10 bar builders over an
   opaque-handle C ABI: the hub any C-capable language (C, C++, Go, C#, Java, R)
-  links against, complementing the native Python/Node/WASM bindings. Ships C
+  links against, complementing the native Python/Node/WASM bindings. Ships a
-  smoke + streaming examples and an optional `wickra.hpp` C++ RAII wrapper.
+  full example suite (streaming, backtest, multi-timeframe, OpenMP parallel
+  fan-out, three educational strategies, and Binance fetch/live over `curl`)
+  mirroring the other bindings, plus an optional `wickra.hpp` C++ RAII wrapper.
 
 ## [0.7.4] - 2026-06-08
 - **Three-Line Break** — Three-line-break bars (reversal needs N-line break) (`THREE_LINE_BREAK_BARS`).

CONTRIBUTING.md

@@ -104,8 +104,8 @@ installed. Dependabot also keeps the `.github/requirements` pins current.
   of `update` calls.
 - **Bindings.** A change to a public indicator API must be mirrored across the
   Python, Node, and WASM bindings, including their type stubs / `.d.ts`. The C ABI
-  (`bindings/c`) is generated from the core, so regenerate it (the ScriptHelpers
+  (`bindings/c`) is generated from the core, so regenerate it from the core and
-  `capi` wrapper) and commit `src/lib.rs` + `include/wickra.h`.
+  commit `src/lib.rs` + `include/wickra.h`.
 - **Docs.** Update the relevant page on the
   [documentation site](https://docs.wickra.org) and the
   `README.md` when behaviour or the public API changes. The docs live in

SECURITY.md

@@ -58,7 +58,11 @@ artifacts, and (4) a healthy dependency supply chain.
 
 - *Memory safety* — the core and all bindings are written in Rust. The crates
   forbid or minimise `unsafe`, so the compiler guarantees memory and thread
-  safety for the indicator logic.
+  safety for the indicator logic. The one exception is the C ABI
+  ([`bindings/c`](bindings/c)), whose thin FFI shim is necessarily `unsafe`
+  because it dereferences caller-supplied pointers; it adds no indicator logic,
+  validates every handle for NULL, and never lets a panic cross the boundary, so
+  the safe core's guarantees still cover all computation.
 - *Input robustness* — every indicator validates its parameters and rejects
   non-finite inputs at construction; behaviour on edge cases (flat markets,
   warmup, reset) is pinned by unit tests, and the public update paths are

THREAT_MODEL.md

@@ -3,8 +3,9 @@
 This document describes Wickra's attack surface and the threats considered,
 together with their mitigations. It complements the security assurance case in
 [`SECURITY.md`](SECURITY.md). Wickra is a computational technical-analysis
-library (a Rust core with Python, Node.js and WebAssembly bindings), not a
+library (a Rust core with Python, Node.js and WebAssembly bindings plus a C ABI),
-network service or trading system; the attack surface is correspondingly small.
+not a network service or trading system; the attack surface is correspondingly
+small.
 
 ## Assets
 
@@ -31,6 +32,7 @@ network service or trading system; the attack surface is correspondingly small.
 | Threat | Mitigation |
 | --- | --- |
 | Memory-safety exploit (buffer overflow, UAF) via crafted input | Pure safe Rust; `unsafe` is forbidden/minimised, so the compiler precludes these classes. |
+| Misuse of the C ABI FFI boundary (invalid/dangling handle, undersized batch buffer) | The C ABI (`bindings/c`) is the sole `unsafe` surface. Its shim adds no logic, NULL-checks every handle (returning `NaN`/no-op), writes only into caller-sized buffers, and catches panics so none cross the boundary. A caller passing a non-NULL but dangling pointer is undefined behaviour by C's own contract — out of scope, the same as any C library. |
 | Denial of service via malformed/degenerate input (NaN, infinities, extreme magnitudes) | Indicators reject non-finite inputs and validate parameters at construction; update paths are exercised by coverage-guided fuzzing and unit tests for edge cases. |
 | Silently incorrect results | 100% line coverage on the core crate; reference-value tests against known-good sources; streaming/batch parity tests. |
 | Integer overflow / panics | `clippy::pedantic` with `-D warnings`; debug assertions and overflow checks enabled in test/fuzz builds. |

bindings/c/src/lib.rs

@@ -11,9 +11,8 @@
 //! - `wickra_<ind>_free(h)` — destroy the handle. Every `_new` must be paired
 //!   with exactly one `_free`; there is no RAII across the C boundary.
 //!
-//! GENERATED by the `ScriptHelpers` `capi` wrapper from the Rust core. Do not edit
+//! GENERATED from the Wickra core. Do not edit by hand — regenerate from the
-//! by hand — edit the generator and regenerate, then commit this file and
+//! core and commit this file together with `include/wickra.h`.
-//! `include/wickra.h`.
 
 use core::ptr;
 use core::slice;

bindings/node/README.md

@@ -9,7 +9,8 @@
 prebuilt native binary, no system dependencies.**
 
 Wickra is a multi-language technical-analysis library with a Rust core and
-bindings for Python, Node.js, and WebAssembly. Every indicator is an O(1)
+bindings for Python, Node.js and WebAssembly, plus a C ABI for C/C++ and any
+other C-capable language. Every indicator is an O(1)
 streaming state machine, so live trading bots and historical backtests share
 the exact same implementation. This package is the Node.js binding (napi-rs);
 it exposes 200+ streaming-first indicators across sixteen families.
@@ -55,8 +56,9 @@ the main repository and documentation site:
 - **Docs** (quickstarts, cookbook, TA-Lib migration): <https://docs.wickra.org>
 - **Runnable examples:** [`examples/node/`](https://github.com/wickra-lib/wickra/tree/main/examples/node)
 
-Wickra ships four bindings — Python, Node.js, WebAssembly, and Rust — that all
+Wickra ships native bindings for Python, Node.js, WebAssembly and Rust, plus a
-expose the same indicators from the shared, `unsafe`-forbidden Rust core.
+C ABI hub that any C-capable language (C, C++, Go, C#, Java, R) links against —
+all exposing the same indicators from the shared, `unsafe`-forbidden Rust core.
 
 ## Disclaimer
 

bindings/python/README.md

@@ -9,7 +9,8 @@
 system dependencies, no C build tooling.**
 
 Wickra is a multi-language technical-analysis library with a Rust core and
-bindings for Python, Node.js, and WebAssembly. Every indicator is an O(1)
+bindings for Python, Node.js and WebAssembly, plus a C ABI for C/C++ and any
+other C-capable language. Every indicator is an O(1)
 streaming state machine, so live trading bots and historical backtests share
 the exact same implementation. This package is the Python binding (PyO3); it
 exposes 200+ streaming-first indicators across sixteen families.
@@ -54,8 +55,9 @@ the main repository and documentation site:
 - **Docs** (quickstarts, cookbook, TA-Lib migration): <https://docs.wickra.org>
 - **Runnable examples:** [`examples/python/`](https://github.com/wickra-lib/wickra/tree/main/examples/python)
 
-Wickra ships four bindings — Python, Node.js, WebAssembly, and Rust — that all
+Wickra ships native bindings for Python, Node.js, WebAssembly and Rust, plus a
-expose the same indicators from the shared, `unsafe`-forbidden Rust core.
+C ABI hub that any C-capable language (C, C++, Go, C#, Java, R) links against —
+all exposing the same indicators from the shared, `unsafe`-forbidden Rust core.
 
 ## Disclaimer
 

bindings/wasm/README.md

@@ -9,7 +9,8 @@
 wickra-wasm` — pure WebAssembly, runs anywhere a modern JS engine does.**
 
 Wickra is a multi-language technical-analysis library with a Rust core and
-bindings for Python, Node.js, and WebAssembly. Every indicator is an O(1)
+bindings for Python, Node.js and WebAssembly, plus a C ABI for C/C++ and any
+other C-capable language. Every indicator is an O(1)
 streaming state machine, so live trading dashboards and historical backtests
 share the exact same implementation. This package is the WebAssembly binding
 (wasm-bindgen, built for the `web` target); it exposes 200+ streaming-first
@@ -54,8 +55,9 @@ the main repository and documentation site:
 - **Docs** (quickstarts, cookbook, TA-Lib migration): <https://docs.wickra.org>
 - **Runnable browser examples:** [`examples/wasm/`](https://github.com/wickra-lib/wickra/tree/main/examples/wasm)
 
-Wickra ships four bindings — Python, Node.js, WebAssembly, and Rust — that all
+Wickra ships native bindings for Python, Node.js, WebAssembly and Rust, plus a
-expose the same indicators from the shared, `unsafe`-forbidden Rust core.
+C ABI hub that any C-capable language (C, C++, Go, C#, Java, R) links against —
+all exposing the same indicators from the shared, `unsafe`-forbidden Rust core.
 
 ## Disclaimer
 

examples/README.md

@@ -31,9 +31,23 @@ the examples via CMake:
 | Example | What it does | CMake target |
 | --- | --- | --- |
 | `smoke.c` | Links the generated header + library and asserts SMA streaming / batch values across the boundary. | `smoke` |
-| `streaming.c` | Feed a tick stream through an EMA, printing each value (NaN during warmup). | `streaming` |
+| `streaming.c` | Feed a synthetic price series through SMA / EMA / RSI / MACD tick by tick. | `streaming` |
+| `backtest.c` | Basket of indicators over an OHLCV CSV; defaults to the bundled BTCUSDT daily dataset. | `backtest` |
+| `multi_timeframe.c` | Resample the bundled 1-minute CSV to 5m / 15m / 1h / 4h / 1d and print indicators per timeframe. | `multi_timeframe` |
+| `parallel_assets.c` | Serial vs OpenMP fan-out over a synthetic panel (one handle per asset), with speedup. | `parallel_assets` |
+| `strategy_rsi_mean_reversion.c` | Hourly BTCUSDT mean-reversion using RSI(14) thresholds, with PnL / Sharpe / max-DD summary. | `strategy_rsi_mean_reversion` |
+| `strategy_macd_adx.c` | Hourly BTCUSDT trend-follower: MACD crossover entries gated by ADX(14) > 20. | `strategy_macd_adx` |
+| `strategy_bollinger_squeeze.c` | Daily BTCUSDT Bollinger-squeeze breakout with ATR(14) stop. | `strategy_bollinger_squeeze` |
+| `fetch_btcusdt.c` | Download real BTCUSDT klines from the Binance REST API into `examples/data/` (shells out to `curl`). | `fetch_btcusdt` |
+| `live_binance.c` | Poll the Binance REST klines endpoint via `curl` and stream closed candles through RSI(14). | `live_binance` |
 | `smoke.cpp` | C++ RAII via `wickra::Handle` from [`wickra.hpp`](../bindings/c/include/wickra.hpp): construct, move, auto-free. | `cpp_smoke` |
 
+The data-driven examples (`backtest`, `multi_timeframe`, `parallel_assets`, the
+three `strategy_*`) build against the bundled datasets and run under `ctest`.
+`fetch_btcusdt` and `live_binance` reach the network, so they are built but not
+run in CI; run them by hand. `parallel_assets` links OpenMP when the toolchain
+provides it and falls back to a single-threaded run otherwise.
+
 ## Python — `examples/python/`
 
 | Example | What it does | Run |

examples/c/CMakeLists.txt

@@ -8,6 +8,15 @@ if(NOT DEFINED WICKRA_LIB_DIR)
 endif()
 set(WICKRA_INCLUDE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../../bindings/c/include")
 
+# Absolute path to the bundled OHLCV datasets, baked into the data-driven
+# examples as a compile definition so they run from any working directory (the
+# C counterpart of the Rust examples' CARGO_MANIFEST_DIR).
+get_filename_component(WICKRA_DATA_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../data" ABSOLUTE)
+
+# OpenMP is optional: parallel_assets links it when present and falls back to a
+# single-threaded run otherwise.
+find_package(OpenMP QUIET)
+
 # Pick the right link target per platform/toolchain.
 #  - MSVC links the generated import library (wickra.dll.lib).
 #  - MinGW/gcc on Windows links the DLL directly.
@@ -27,12 +36,15 @@ endif()
 
 enable_testing()
 
-# Build one example, link it to the Wickra library, run it as a ctest. On Windows
+# Build one example and link it to the Wickra library. On Windows the DLL is
-# the DLL is copied next to the executable so the loader finds it at run time.
+# copied next to the executable so the loader finds it at run time. With
-function(add_wickra_example name source)
+# register_test=TRUE the example is also run as a ctest; network examples pass
+# FALSE (they are built only, never run in CI).
+function(add_wickra_example name source register_test)
     add_executable(${name} ${source})
     target_include_directories(${name} PRIVATE "${WICKRA_INCLUDE_DIR}")
     target_link_libraries(${name} PRIVATE "${WICKRA_LINK_LIB}")
+    target_compile_definitions(${name} PRIVATE "WICKRA_DATA_DIR=\"${WICKRA_DATA_DIR}\"")
     if(UNIX AND NOT APPLE)
         target_link_libraries(${name} PRIVATE m)
     endif()
@@ -41,13 +53,30 @@ function(add_wickra_example name source)
             COMMAND ${CMAKE_COMMAND} -E copy_if_different
                     "${WICKRA_RUNTIME}" "$<TARGET_FILE_DIR:${name}>")
     endif()
-    add_test(NAME ${name} COMMAND ${name})
+    if(register_test)
-    if(NOT WIN32)
+        add_test(NAME ${name} COMMAND ${name})
-        set_tests_properties(${name} PROPERTIES
+        if(NOT WIN32)
-            ENVIRONMENT "LD_LIBRARY_PATH=${WICKRA_LIB_DIR};DYLD_LIBRARY_PATH=${WICKRA_LIB_DIR}")
+            set_tests_properties(${name} PROPERTIES
+                ENVIRONMENT "LD_LIBRARY_PATH=${WICKRA_LIB_DIR};DYLD_LIBRARY_PATH=${WICKRA_LIB_DIR}")
+        endif()
     endif()
 endfunction()
 
-add_wickra_example(smoke smoke.c)         # links the boundary, asserts values
+# Offline examples — built and run as ctests.
-add_wickra_example(streaming streaming.c) # runnable streaming demo
+add_wickra_example(smoke smoke.c TRUE)                 # links the boundary, asserts values
-add_wickra_example(cpp_smoke smoke.cpp)   # C++ RAII wrapper (wickra.hpp)
+add_wickra_example(streaming streaming.c TRUE)         # multi-indicator tick stream
+add_wickra_example(cpp_smoke smoke.cpp TRUE)           # C++ RAII wrapper (wickra.hpp)
+add_wickra_example(backtest backtest.c TRUE)           # indicator basket over a CSV
+add_wickra_example(multi_timeframe multi_timeframe.c TRUE)  # resample + per-TF indicators
+add_wickra_example(parallel_assets parallel_assets.c TRUE)  # serial vs OpenMP fan-out
+add_wickra_example(strategy_rsi_mean_reversion strategy_rsi_mean_reversion.c TRUE)
+add_wickra_example(strategy_macd_adx strategy_macd_adx.c TRUE)
+add_wickra_example(strategy_bollinger_squeeze strategy_bollinger_squeeze.c TRUE)
+
+if(OpenMP_C_FOUND)
+    target_link_libraries(parallel_assets PRIVATE OpenMP::OpenMP_C)
+endif()
+
+# Network examples — built (so they stay compilable) but not run in CI.
+add_wickra_example(fetch_btcusdt fetch_btcusdt.c FALSE) # downloads CSVs via curl
+add_wickra_example(live_binance live_binance.c FALSE)   # polls Binance REST via curl

examples/c/README.md

@@ -50,6 +50,28 @@ Expected output:
 OK: wickra C ABI smoke passed (SMA streaming + batch + reset + NULL-safety + free)
 ```
 
+## The examples
+
+| Example | What it does |
+|---------|--------------|
+| `smoke.c` | Links the boundary and asserts SMA streaming / batch / reset / NULL-safety values. |
+| `streaming.c` | Feeds a synthetic price series through SMA / EMA / RSI / MACD tick by tick. |
+| `backtest.c` | Runs an indicator basket over an OHLCV CSV (defaults to the bundled daily dataset). |
+| `multi_timeframe.c` | Resamples the bundled 1-minute CSV to 5m / 15m / 1h / 4h / 1d and prints indicators per timeframe. |
+| `parallel_assets.c` | Serial vs OpenMP fan-out over a synthetic panel (one handle per asset), with speedup. |
+| `strategy_rsi_mean_reversion.c` | Hourly RSI(14) mean-reversion with a PnL / Sharpe / max-drawdown summary. |
+| `strategy_macd_adx.c` | Hourly MACD crossover gated by ADX(14) > 20. |
+| `strategy_bollinger_squeeze.c` | Daily Bollinger-squeeze breakout with an ATR(14) stop. |
+| `fetch_btcusdt.c` | Downloads BTCUSDT klines from the Binance REST API into `examples/data/` (shells out to `curl`). |
+| `live_binance.c` | Polls the Binance REST klines endpoint via `curl` and streams closed candles through RSI(14). |
+| `smoke.cpp` | C++ RAII via `wickra::Handle` from [`wickra.hpp`](../../bindings/c/include/wickra.hpp). |
+
+`ctest` builds and runs every example except `fetch_btcusdt` and `live_binance`,
+which reach the network and are built only — run those two by hand. The C ABI
+exposes only the indicators, not the `wickra-data` IO layer, so the examples read
+CSV ([`wickra_csv.h`](wickra_csv.h)) and resample themselves; the network ones
+shell out to the system `curl` rather than adding an HTTP/TLS dependency.
+
 ## Usage shape
 
 Every indicator follows the same five-function pattern over an opaque handle:

examples/c/backtest.c

@@ -0,0 +1,139 @@
+/* Backtest a basket of indicators against an OHLCV CSV with the Wickra C ABI.
+ *
+ * The C counterpart of `examples/rust/src/bin/backtest.rs` and
+ * `examples/node/backtest.js`: load an OHLCV file, run a basket of indicators
+ * (scalar ones via `_batch`, candle ones streamed bar by bar), and print the
+ * most recent value of each. Defaults to the bundled BTCUSDT daily dataset.
+ *
+ * Build (after `cargo build -p wickra-c --release`):
+ *   cc examples/c/backtest.c -I bindings/c/include -L target/release -lwickra -lm -o backtest
+ *   ./backtest [path/to/ohlcv.csv]
+ */
+
+#define WICKRA_CSV_IMPL
+#include "wickra.h"
+#include "wickra_csv.h"
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#ifndef WICKRA_DATA_DIR
+#define WICKRA_DATA_DIR "../data"
+#endif
+
+/* Last finite value of a scalar batch result, or NaN if none warmed up. */
+static double last_finite(const double *v, size_t n) {
+    for (size_t i = n; i-- > 0;) {
+        if (isfinite(v[i])) {
+            return v[i];
+        }
+    }
+    return NAN;
+}
+
+int main(int argc, char **argv) {
+    const char *path = (argc > 1) ? argv[1] : WICKRA_DATA_DIR "/btcusdt-1d.csv";
+
+    WickraCandle *candles = NULL;
+    size_t n = wickra_load_csv(path, &candles);
+    if (n == 0) {
+        fprintf(stderr, "backtest: no candles read from %s\n", path);
+        return 1;
+    }
+
+    double *closes = (double *)malloc(n * sizeof(*closes));
+    double *rsi_out = (double *)malloc(n * sizeof(*rsi_out));
+    double *ema_out = (double *)malloc(n * sizeof(*ema_out));
+    struct Rsi *rsi = wickra_rsi_new(14);
+    struct Ema *ema = wickra_ema_new(20);
+    struct BollingerBands *bb = wickra_bollinger_bands_new(20, 2.0);
+    struct MacdIndicator *macd = wickra_macd_indicator_new(12, 26, 9);
+    struct Atr *atr = wickra_atr_new(14);
+    struct Adx *adx = wickra_adx_new(14);
+    struct Obv *obv = wickra_obv_new();
+    if (closes == NULL || rsi_out == NULL || ema_out == NULL || rsi == NULL ||
+        ema == NULL || bb == NULL || macd == NULL || atr == NULL || adx == NULL ||
+        obv == NULL) {
+        fprintf(stderr, "backtest: allocation failed\n");
+        return 1;
+    }
+
+    for (size_t i = 0; i < n; ++i) {
+        closes[i] = candles[i].close;
+    }
+
+    /* Scalar indicators: one batch call over the close series. */
+    wickra_rsi_batch(rsi, closes, rsi_out, n);
+    wickra_ema_batch(ema, closes, ema_out, n);
+
+    /* Multi-output and candle indicators: streamed bar by bar, keeping the
+     * last value each one produced. */
+    WickraBollingerOutput last_bb = {0};
+    int have_bb = 0;
+    WickraMacdOutput last_macd = {0};
+    int have_macd = 0;
+    WickraAdxOutput last_adx = {0};
+    int have_adx = 0;
+    double last_atr = NAN;
+    double last_obv = NAN;
+    for (size_t i = 0; i < n; ++i) {
+        const WickraCandle *c = &candles[i];
+        WickraBollingerOutput bo;
+        if (wickra_bollinger_bands_update(bb, c->close, &bo)) {
+            last_bb = bo;
+            have_bb = 1;
+        }
+        WickraMacdOutput mo;
+        if (wickra_macd_indicator_update(macd, c->close, &mo)) {
+            last_macd = mo;
+            have_macd = 1;
+        }
+        double av = wickra_atr_update(atr, c->open, c->high, c->low, c->close,
+                                      c->volume, c->timestamp);
+        if (isfinite(av)) {
+            last_atr = av;
+        }
+        WickraAdxOutput ao;
+        if (wickra_adx_update(adx, c->open, c->high, c->low, c->close, c->volume,
+                              c->timestamp, &ao)) {
+            last_adx = ao;
+            have_adx = 1;
+        }
+        double ov = wickra_obv_update(obv, c->open, c->high, c->low, c->close,
+                                      c->volume, c->timestamp);
+        if (isfinite(ov)) {
+            last_obv = ov;
+        }
+    }
+
+    printf("backtest summary for %s (%llu bars)\n", path, (unsigned long long)n);
+    printf("  RSI(14)  = %9.4f\n", last_finite(rsi_out, n));
+    printf("  EMA(20)  = %9.4f\n", last_finite(ema_out, n));
+    if (have_bb) {
+        printf("  BB(20,2) upper=%9.4f  middle=%9.4f  lower=%9.4f  sd=%8.4f\n",
+               last_bb.upper, last_bb.middle, last_bb.lower, last_bb.stddev);
+    }
+    if (have_macd) {
+        printf("  MACD     macd=%9.4f  signal=%9.4f  hist=%9.4f\n", last_macd.macd,
+               last_macd.signal, last_macd.histogram);
+    }
+    printf("  ATR(14)  = %9.4f\n", last_atr);
+    if (have_adx) {
+        printf("  ADX(14)  +DI=%6.2f  -DI=%6.2f  ADX=%6.2f\n", last_adx.plus_di,
+               last_adx.minus_di, last_adx.adx);
+    }
+    printf("  OBV      = %14.2f\n", last_obv);
+
+    wickra_rsi_free(rsi);
+    wickra_ema_free(ema);
+    wickra_bollinger_bands_free(bb);
+    wickra_macd_indicator_free(macd);
+    wickra_atr_free(atr);
+    wickra_adx_free(adx);
+    wickra_obv_free(obv);
+    free(closes);
+    free(rsi_out);
+    free(ema_out);
+    free(candles);
+    return 0;
+}

examples/c/fetch_btcusdt.c

@@ -0,0 +1,311 @@
+/* Download real BTCUSDT spot candles from the Binance REST API and write them as
+ * CSV datasets under examples/data/ — the C counterpart of
+ * `examples/rust/src/bin/fetch_btcusdt.rs` and `examples/node/fetch_btcusdt.js`.
+ *
+ * Like the Rust example, HTTPS is handled by shelling out to the system `curl`
+ * (shipped with Windows 10+, macOS and every Linux distro), so this example adds
+ * no HTTP/TLS dependency. Each klines response is capped at 1000 rows, so larger
+ * datasets are paginated backwards through `endTime`. Only fully closed candles
+ * are kept.
+ *
+ * This example talks to the network, so it is built but NOT run as a ctest.
+ *
+ * Build (after `cargo build -p wickra-c --release`):
+ *   cc examples/c/fetch_btcusdt.c -I bindings/c/include -L target/release -lwickra -lm -o fetch_btcusdt
+ *   ./fetch_btcusdt
+ */
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#ifdef _WIN32
+#define POPEN _popen
+#define PCLOSE _pclose
+#else
+#define POPEN popen
+#define PCLOSE pclose
+#endif
+
+#ifndef WICKRA_DATA_DIR
+#define WICKRA_DATA_DIR "../data"
+#endif
+
+#define SYMBOL "BTCUSDT"
+#define PAGE_LIMIT 1000
+
+typedef struct {
+    int64_t open_time;
+    int64_t close_time;
+    double open, high, low, close, volume;
+} Kline;
+
+typedef struct {
+    const char *interval;
+    const char *file;
+    size_t target;
+} Dataset;
+
+/* One dataset per timeframe. The monthly file is `btcusdt-1month.csv`, not
+ * `-1M`, so it does not collide with `-1m` on case-insensitive filesystems. */
+static const Dataset DATASETS[] = {
+    {"1m", "btcusdt-1m.csv", 50000},  {"5m", "btcusdt-5m.csv", 10000},
+    {"15m", "btcusdt-15m.csv", 10000}, {"1h", "btcusdt-1h.csv", 10000},
+    {"12h", "btcusdt-12h.csv", 5000}, {"1d", "btcusdt-1d.csv", 5000},
+    {"1M", "btcusdt-1month.csv", 5000},
+};
+
+/* Run `curl <url>` and return its stdout as a malloc'd, NUL-terminated buffer
+ * (caller frees), or NULL on failure. */
+static char *curl_get(const char *url) {
+    char cmd[512];
+    snprintf(cmd, sizeof(cmd),
+             "curl --silent --show-error --fail --max-time 30 \"%s\"", url);
+    FILE *p = POPEN(cmd, "r");
+    if (p == NULL) {
+        fprintf(stderr, "could not run curl (install it / put it on PATH)\n");
+        return NULL;
+    }
+    size_t cap = 1 << 16, len = 0;
+    char *buf = (char *)malloc(cap);
+    if (buf == NULL) {
+        PCLOSE(p);
+        return NULL;
+    }
+    size_t got;
+    char tmp[8192];
+    while ((got = fread(tmp, 1, sizeof(tmp), p)) > 0) {
+        if (len + got + 1 > cap) {
+            cap *= 2;
+            char *grown = (char *)realloc(buf, cap);
+            if (grown == NULL) {
+                free(buf);
+                PCLOSE(p);
+                return NULL;
+            }
+            buf = grown;
+        }
+        memcpy(buf + len, tmp, got);
+        len += got;
+    }
+    int rc = PCLOSE(p);
+    buf[len] = '\0';
+    if (rc != 0 || len == 0) {
+        fprintf(stderr, "curl failed for %s\n", url);
+        free(buf);
+        return NULL;
+    }
+    return buf;
+}
+
+/* Parse a Binance klines JSON array. Each row is
+ * [openTime, "open", "high", "low", "close", "volume", closeTime, ...].
+ * Appends parsed rows to *rows (grown via realloc) and returns the new count. */
+static size_t parse_klines(const char *body, Kline **rows, size_t count, size_t *cap) {
+    int depth = 0;
+    int in_string = 0;
+    int field = -1; /* -1 = not inside a row yet */
+    char tok[64];
+    size_t tok_len = 0;
+    Kline cur = {0};
+
+    for (const char *s = body; *s; ++s) {
+        char ch = *s;
+        if (in_string) {
+            if (ch == '"') {
+                in_string = 0;
+            } else if (tok_len + 1 < sizeof(tok)) {
+                tok[tok_len++] = ch;
+            }
+            continue;
+        }
+        switch (ch) {
+        case '[':
+            depth++;
+            if (depth == 2) {
+                field = 0;
+                tok_len = 0;
+                memset(&cur, 0, sizeof(cur));
+            }
+            break;
+        case ']':
+            if (depth == 2) {
+                /* close the final field of this row, then emit it */
+                tok[tok_len] = '\0';
+                if (field == 6) {
+                    cur.close_time = strtoll(tok, NULL, 10);
+                }
+                if (*cap == count) {
+                    *cap = *cap ? *cap * 2 : 1024;
+                    Kline *grown = (Kline *)realloc(*rows, *cap * sizeof(Kline));
+                    if (grown == NULL) {
+                        return count;
+                    }
+                    *rows = grown;
+                }
+                (*rows)[count++] = cur;
+                field = -1;
+            }
+            depth--;
+            break;
+        case '"':
+            in_string = 1;
+            break;
+        case ',':
+            if (depth == 2) {
+                tok[tok_len] = '\0';
+                switch (field) {
+                case 0: cur.open_time = strtoll(tok, NULL, 10); break;
+                case 1: cur.open = strtod(tok, NULL); break;
+                case 2: cur.high = strtod(tok, NULL); break;
+                case 3: cur.low = strtod(tok, NULL); break;
+                case 4: cur.close = strtod(tok, NULL); break;
+                case 5: cur.volume = strtod(tok, NULL); break;
+                case 6: cur.close_time = strtoll(tok, NULL, 10); break;
+                default: break;
+                }
+                field++;
+                tok_len = 0;
+            }
+            break;
+        default:
+            if (depth == 2 && tok_len + 1 < sizeof(tok)) {
+                tok[tok_len++] = ch;
+            }
+            break;
+        }
+    }
+    return count;
+}
+
+static int cmp_open(const void *a, const void *b) {
+    int64_t x = ((const Kline *)a)->open_time;
+    int64_t y = ((const Kline *)b)->open_time;
+    return (x > y) - (x < y);
+}
+
+/* Paginate backwards until `target` closed candles are collected. */
+static size_t collect(const char *interval, size_t target, int64_t now_ms,
+                      Kline **out) {
+    Kline *rows = NULL;
+    size_t count = 0, cap = 0;
+    int64_t end_time = 0; /* 0 = no endTime cap (most recent page) */
+    int pages = 0;
+
+    for (;;) {
+        char url[256];
+        if (end_time > 0) {
+            snprintf(url, sizeof(url),
+                     "https://api.binance.com/api/v3/klines?symbol=%s&interval=%s"
+                     "&limit=%d&endTime=%lld",
+                     SYMBOL, interval, PAGE_LIMIT, (long long)end_time);
+        } else {
+            snprintf(url, sizeof(url),
+                     "https://api.binance.com/api/v3/klines?symbol=%s&interval=%s"
+                     "&limit=%d",
+                     SYMBOL, interval, PAGE_LIMIT);
+        }
+        char *body = curl_get(url);
+        if (body == NULL) {
+            free(rows);
+            return 0;
+        }
+        Kline *page = NULL;
+        size_t page_cap = 0;
+        size_t page_n = parse_klines(body, &page, 0, &page_cap);
+        free(body);
+        pages++;
+
+        int64_t oldest_open = INT64_MAX;
+        for (size_t i = 0; i < page_n; ++i) {
+            if (page[i].open_time < oldest_open) {
+                oldest_open = page[i].open_time;
+            }
+            if (page[i].close_time < now_ms) { /* keep only closed candles */
+                if (count == cap) {
+                    cap = cap ? cap * 2 : 1024;
+                    Kline *grown = (Kline *)realloc(rows, cap * sizeof(Kline));
+                    if (grown == NULL) {
+                        free(page);
+                        free(rows);
+                        return 0;
+                    }
+                    rows = grown;
+                }
+                rows[count++] = page[i];
+            }
+        }
+        fprintf(stderr, "\r  %s: collected %llu candles over %d page(s)...",
+                interval, (unsigned long long)count, pages);
+
+        int page_full = page_n >= PAGE_LIMIT;
+        free(page);
+        if (count >= target || !page_full || oldest_open == INT64_MAX) {
+            break;
+        }
+        end_time = oldest_open - 1;
+    }
+    fprintf(stderr, "\n");
+
+    /* Sort ascending, drop duplicate open times, keep the most recent target. */
+    qsort(rows, count, sizeof(Kline), cmp_open);
+    size_t uniq = 0;
+    for (size_t i = 0; i < count; ++i) {
+        if (uniq == 0 || rows[i].open_time != rows[uniq - 1].open_time) {
+            rows[uniq++] = rows[i];
+        }
+    }
+    if (uniq > target) {
+        memmove(rows, rows + (uniq - target), target * sizeof(Kline));
+        uniq = target;
+    }
+    *out = rows;
+    return uniq;
+}
+
+static int write_csv(const char *path, const Kline *rows, size_t n) {
+    FILE *f = fopen(path, "w");
+    if (f == NULL) {
+        return 0;
+    }
+    fputs("timestamp,open,high,low,close,volume\n", f);
+    for (size_t i = 0; i < n; ++i) {
+        fprintf(f, "%lld,%g,%g,%g,%g,%g\n", (long long)rows[i].open_time,
+                rows[i].open, rows[i].high, rows[i].low, rows[i].close,
+                rows[i].volume);
+    }
+    fclose(f);
+    return 1;
+}
+
+int main(void) {
+    int64_t now_ms = (int64_t)time(NULL) * 1000;
+
+    printf("Fetching %s klines from Binance into %s\n", SYMBOL, WICKRA_DATA_DIR);
+    size_t n_datasets = sizeof(DATASETS) / sizeof(DATASETS[0]);
+    for (size_t d = 0; d < n_datasets; ++d) {
+        const Dataset *ds = &DATASETS[d];
+        Kline *rows = NULL;
+        size_t n = collect(ds->interval, ds->target, now_ms, &rows);
+        if (n == 0) {
+            fprintf(stderr, "Binance returned no closed candles for %s\n",
+                    ds->interval);
+            free(rows);
+            return 1;
+        }
+        char path[256];
+        snprintf(path, sizeof(path), "%s/%s", WICKRA_DATA_DIR, ds->file);
+        if (!write_csv(path, rows, n)) {
+            fprintf(stderr, "could not write %s\n", path);
+            free(rows);
+            return 1;
+        }
+        printf("  %3s  %6llu candles  ->  %s\n", ds->interval, (unsigned long long)n,
+               path);
+        free(rows);
+    }
+    printf("Done — %llu datasets written.\n", (unsigned long long)n_datasets);
+    return 0;
+}

examples/c/live_binance.c

@@ -0,0 +1,154 @@
+/* Live BTCUSDT indicator with the Wickra C ABI.
+ *
+ * The C counterpart of `examples/rust/src/bin/live_binance.rs`,
+ * `examples/python/live_trading.py` and `examples/node/live_trading.js`. Those
+ * stream Binance over a WebSocket; the C ABI ships only the indicators and no
+ * socket layer, so this example polls the Binance REST klines endpoint via the
+ * system `curl` once per interval and feeds each newly *closed* candle into a
+ * streaming RSI(14). Same "live feed -> incremental indicator" shape, no extra
+ * dependency.
+ *
+ * This example talks to the network and runs until interrupted (Ctrl+C), so it
+ * is built but NOT run as a ctest.
+ *
+ * Build (after `cargo build -p wickra-c --release`):
+ *   cc examples/c/live_binance.c -I bindings/c/include -L target/release -lwickra -lm -o live_binance
+ *   ./live_binance [SYMBOL]
+ */
+
+#include "wickra.h"
+#include <math.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef _WIN32
+#include <windows.h>
+#define SLEEP_MS(ms) Sleep(ms)
+#define POPEN _popen
+#define PCLOSE _pclose
+#else
+#include <time.h>
+#define POPEN popen
+#define PCLOSE pclose
+static void SLEEP_MS(long ms) {
+    struct timespec ts = {ms / 1000, (ms % 1000) * 1000000L};
+    nanosleep(&ts, NULL);
+}
+#endif
+
+/* Run `curl <url>` and return stdout as a malloc'd, NUL-terminated buffer. */
+static char *curl_get(const char *url) {
+    char cmd[512];
+    snprintf(cmd, sizeof(cmd),
+             "curl --silent --show-error --fail --max-time 15 \"%s\"", url);
+    FILE *p = POPEN(cmd, "r");
+    if (p == NULL) {
+        return NULL;
+    }
+    size_t cap = 1 << 15, len = 0;
+    char *buf = (char *)malloc(cap);
+    if (buf == NULL) {
+        PCLOSE(p);
+        return NULL;
+    }
+    size_t got;
+    char tmp[4096];
+    while ((got = fread(tmp, 1, sizeof(tmp), p)) > 0) {
+        if (len + got + 1 > cap) {
+            cap *= 2;
+            char *grown = (char *)realloc(buf, cap);
+            if (grown == NULL) {
+                free(buf);
+                PCLOSE(p);
+                return NULL;
+            }
+            buf = grown;
+        }
+        memcpy(buf + len, tmp, got);
+        len += got;
+    }
+    int rc = PCLOSE(p);
+    buf[len] = '\0';
+    if (rc != 0 || len == 0) {
+        free(buf);
+        return NULL;
+    }
+    return buf;
+}
+
+/* Extract the first kline's open time and close price from a klines response of
+ * the form [[openTime,"open","high","low","close",...],...]. Returns 1 on
+ * success. The first row (limit=2) is the most recent fully closed candle. */
+static int first_kline(const char *body, int64_t *open_time, double *close) {
+    const char *s = strchr(body, '[');
+    if (s == NULL) {
+        return 0;
+    }
+    s = strchr(s + 1, '['); /* into the first row */
+    if (s == NULL) {
+        return 0;
+    }
+    s++;
+    char tok[64];
+    int field = 0;
+    while (*s && *s != ']') {
+        size_t tl = 0;
+        while (*s && *s != ',' && *s != ']') {
+            if (*s != '"' && tl + 1 < sizeof(tok)) {
+                tok[tl++] = *s;
+            }
+            s++;
+        }
+        tok[tl] = '\0';
+        if (field == 0) {
+            *open_time = strtoll(tok, NULL, 10);
+        } else if (field == 4) {
+            *close = strtod(tok, NULL);
+            return 1;
+        }
+        field++;
+        if (*s == ',') {
+            s++;
+        }
+    }
+    return 0;
+}
+
+int main(int argc, char **argv) {
+    const char *symbol = (argc > 1) ? argv[1] : "BTCUSDT";
+    char url[256];
+    snprintf(url, sizeof(url),
+             "https://api.binance.com/api/v3/klines?symbol=%s&interval=1m&limit=2",
+             symbol);
+
+    struct Rsi *rsi = wickra_rsi_new(14);
+    if (rsi == NULL) {
+        fprintf(stderr, "failed to create RSI\n");
+        return 1;
+    }
+    printf("Listening for %s 1m closes (REST poll, Ctrl+C to stop)...\n", symbol);
+
+    int64_t last_open = 0;
+    for (;;) {
+        char *body = curl_get(url);
+        if (body != NULL) {
+            int64_t open_time = 0;
+            double close = 0.0;
+            if (first_kline(body, &open_time, &close) && open_time != last_open) {
+                last_open = open_time;
+                double v = wickra_rsi_update(rsi, close);
+                if (isfinite(v)) {
+                    printf("%s  close=%.4f  rsi=%.2f\n", symbol, close, v);
+                } else {
+                    printf("%s  close=%.4f  rsi=...warmup\n", symbol, close);
+                }
+                fflush(stdout);
+            }
+            free(body);
+        }
+        SLEEP_MS(2000);
+    }
+    /* Unreachable in normal use (interrupted by Ctrl+C). */
+}

examples/c/multi_timeframe.c

@@ -0,0 +1,151 @@
+/* Multi-timeframe indicators with the Wickra C ABI.
+ *
+ * The C counterpart of `examples/rust/src/bin/multi_timeframe.rs` and
+ * `examples/python/multi_timeframe.py`: read the bundled 1-minute BTCUSDT CSV
+ * (or a path on the command line), resample it to 5m / 15m / 1h / 4h / 1d, and
+ * print the last RSI(14), MACD(12,26,9) histogram and ADX(14) at each timeframe.
+ *
+ * The Rust/Python stack resamples through `wickra-data`; the C ABI ships only
+ * the indicators, so the time-bucket aggregation is done here (open = first,
+ * high = max, low = min, close = last, volume = sum per bucket).
+ *
+ * Build (after `cargo build -p wickra-c --release`):
+ *   cc examples/c/multi_timeframe.c -I bindings/c/include -L target/release -lwickra -lm -o multi_timeframe
+ *   ./multi_timeframe [path/to/1m.csv]
+ */
+
+#define WICKRA_CSV_IMPL
+#include "wickra.h"
+#include "wickra_csv.h"
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#ifndef WICKRA_DATA_DIR
+#define WICKRA_DATA_DIR "../data"
+#endif
+
+#define ONE_MINUTE_MS 60000LL
+
+/* Aggregate `in` into fixed-width time buckets of `tf_ms`. Writes the bucketed
+ * candles into the caller-owned `out` (capacity >= count) and returns how many
+ * buckets were produced. */
+static size_t resample(const WickraCandle *in, size_t count, int64_t tf_ms,
+                       WickraCandle *out) {
+    size_t produced = 0;
+    int open_bucket = 0;
+    int64_t bucket_start = 0;
+    WickraCandle cur = {0};
+    for (size_t i = 0; i < count; ++i) {
+        int64_t b = in[i].timestamp - (in[i].timestamp % tf_ms);
+        if (!open_bucket || b != bucket_start) {
+            if (open_bucket) {
+                out[produced++] = cur;
+            }
+            bucket_start = b;
+            cur = in[i];
+            cur.timestamp = b;
+            open_bucket = 1;
+        } else {
+            if (in[i].high > cur.high) {
+                cur.high = in[i].high;
+            }
+            if (in[i].low < cur.low) {
+                cur.low = in[i].low;
+            }
+            cur.close = in[i].close;
+            cur.volume += in[i].volume;
+        }
+    }
+    if (open_bucket) {
+        out[produced++] = cur;
+    }
+    return produced;
+}
+
+static void summarize(const char *label, const WickraCandle *candles, size_t n) {
+    if (n == 0) {
+        printf("  %-5s (empty)\n", label);
+        return;
+    }
+    struct Rsi *rsi = wickra_rsi_new(14);
+    struct MacdIndicator *macd = wickra_macd_indicator_new(12, 26, 9);
+    struct Adx *adx = wickra_adx_new(14);
+
+    double last_rsi = NAN;
+    double last_hist = NAN;
+    double last_adx = NAN;
+    for (size_t i = 0; i < n; ++i) {
+        const WickraCandle *c = &candles[i];
+        double r = wickra_rsi_update(rsi, c->close);
+        if (isfinite(r)) {
+            last_rsi = r;
+        }
+        WickraMacdOutput m;
+        if (wickra_macd_indicator_update(macd, c->close, &m)) {
+            last_hist = m.histogram;
+        }
+        WickraAdxOutput a;
+        if (wickra_adx_update(adx, c->open, c->high, c->low, c->close, c->volume,
+                              c->timestamp, &a)) {
+            last_adx = a.adx;
+        }
+    }
+
+    char b_rsi[16], b_hist[16], b_adx[16];
+    if (isfinite(last_rsi)) {
+        snprintf(b_rsi, sizeof(b_rsi), "%6.2f", last_rsi);
+    } else {
+        snprintf(b_rsi, sizeof(b_rsi), "    --");
+    }
+    if (isfinite(last_hist)) {
+        snprintf(b_hist, sizeof(b_hist), "%+6.2f", last_hist);
+    } else {
+        snprintf(b_hist, sizeof(b_hist), " --   ");
+    }
+    if (isfinite(last_adx)) {
+        snprintf(b_adx, sizeof(b_adx), "%6.2f", last_adx);
+    } else {
+        snprintf(b_adx, sizeof(b_adx), "    --");
+    }
+    printf("  %-5s bars=%5llu  last_close=%10.2f  rsi=%s  macd_hist=%s  adx=%s\n",
+           label, (unsigned long long)n, candles[n - 1].close, b_rsi, b_hist, b_adx);
+
+    wickra_rsi_free(rsi);
+    wickra_macd_indicator_free(macd);
+    wickra_adx_free(adx);
+}
+
+int main(int argc, char **argv) {
+    const char *path = (argc > 1) ? argv[1] : WICKRA_DATA_DIR "/btcusdt-1m.csv";
+
+    WickraCandle *ones = NULL;
+    size_t n = wickra_load_csv(path, &ones);
+    if (n == 0) {
+        fprintf(stderr, "multi_timeframe: no candles read from %s\n", path);
+        return 1;
+    }
+    /* Resampling only ever produces fewer candles than the 1m source. */
+    WickraCandle *buf = (WickraCandle *)malloc(n * sizeof(*buf));
+    if (buf == NULL) {
+        fprintf(stderr, "multi_timeframe: allocation failed\n");
+        free(ones);
+        return 1;
+    }
+
+    printf("Multi-timeframe view of %s\n", path);
+    summarize("1m", ones, n);
+
+    const struct {
+        const char *label;
+        int64_t minutes;
+    } frames[] = {{"5m", 5}, {"15m", 15}, {"1h", 60}, {"4h", 240}, {"1d", 1440}};
+    for (size_t f = 0; f < sizeof(frames) / sizeof(frames[0]); ++f) {
+        size_t m = resample(ones, n, frames[f].minutes * ONE_MINUTE_MS, buf);
+        summarize(frames[f].label, buf, m);
+    }
+
+    free(buf);
+    free(ones);
+    return 0;
+}

examples/c/parallel_assets.c

@@ -0,0 +1,156 @@
+/* Parallel multi-asset indicator computation with the Wickra C ABI.
+ *
+ * The C counterpart of `examples/rust/src/bin/parallel_assets.rs` (rayon) and
+ * `examples/python/parallel_assets.py` (the Rust extension drops the GIL). The C
+ * ABI is the parallelization primitive itself: each `wickra_<ind>_new` handle is
+ * independent, so the caller fans assets out across threads, one fresh handle per
+ * asset. Here a serial baseline is compared against an OpenMP `parallel for`.
+ *
+ * If the compiler has no OpenMP support the "parallel" pass simply runs the same
+ * single-threaded loop (speedup ~1x) — the result is honest either way.
+ *
+ * Build (after `cargo build -p wickra-c --release`):
+ *   cc -fopenmp examples/c/parallel_assets.c -I bindings/c/include -L target/release -lwickra -lm -o parallel_assets
+ *   ./parallel_assets --assets 200 --bars 5000 --indicator sma
+ */
+
+#include "wickra.h"
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#ifdef _OPENMP
+#include <omp.h>
+#endif
+
+/* Wall-clock seconds (not CPU time, so threaded speedup is measured correctly). */
+static double now_seconds(void) {
+#ifdef _OPENMP
+    return omp_get_wtime();
+#else
+    struct timespec ts;
+    timespec_get(&ts, TIME_UTC);
+    return (double)ts.tv_sec + (double)ts.tv_nsec * 1e-9;
+#endif
+}
+
+typedef enum { IND_SMA, IND_RSI } Which;
+
+/* Deterministic synthetic (assets, bars) panel, flat row-major. Each asset uses
+ * an independent LCG seed so the series are uncorrelated but reproducible. */
+static void synthesize_panel(double *panel, size_t assets, size_t bars) {
+    for (size_t a = 0; a < assets; ++a) {
+        double price = 100.0;
+        uint32_t state = (uint32_t)(1234567u + a) * 2654435761u;
+        for (size_t b = 0; b < bars; ++b) {
+            state = (state * 1103515245u + 12345u) & 0x7FFFFFFFu;
+            double r = (double)state / (double)0x7FFFFFFFu;
+            price += (r - 0.5) * 0.4;
+            panel[a * bars + b] = price;
+        }
+    }
+}
+
+/* Run one asset's series through a fresh handle into its output slice. */
+static void run_one(Which which, const double *prices, double *out, size_t bars) {
+    if (which == IND_SMA) {
+        struct Sma *h = wickra_sma_new(14);
+        wickra_sma_batch(h, prices, out, bars);
+        wickra_sma_free(h);
+    } else {
+        struct Rsi *h = wickra_rsi_new(14);
+        wickra_rsi_batch(h, prices, out, bars);
+        wickra_rsi_free(h);
+    }
+}
+
+int main(int argc, char **argv) {
+    size_t assets = 200;
+    size_t bars = 5000;
+    Which which = IND_SMA;
+    for (int i = 1; i < argc; ++i) {
+        if (strcmp(argv[i], "--assets") == 0 && i + 1 < argc) {
+            assets = (size_t)strtoul(argv[++i], NULL, 10);
+        } else if (strcmp(argv[i], "--bars") == 0 && i + 1 < argc) {
+            bars = (size_t)strtoul(argv[++i], NULL, 10);
+        } else if (strcmp(argv[i], "--indicator") == 0 && i + 1 < argc) {
+            ++i;
+            if (strcmp(argv[i], "sma") == 0) {
+                which = IND_SMA;
+            } else if (strcmp(argv[i], "rsi") == 0) {
+                which = IND_RSI;
+            } else {
+                fprintf(stderr, "--indicator: expected 'sma' or 'rsi'\n");
+                return 1;
+            }
+        } else {
+            fprintf(stderr, "usage: parallel_assets [--assets N] [--bars N] "
+                            "[--indicator sma|rsi]\n");
+            return 1;
+        }
+    }
+    if (assets == 0 || bars == 0) {
+        fprintf(stderr, "--assets and --bars must be positive\n");
+        return 1;
+    }
+
+    const char *ind_name = (which == IND_SMA) ? "sma" : "rsi";
+    printf("Generating %llux%llu synthetic panel...\n", (unsigned long long)assets,
+           (unsigned long long)bars);
+    double *panel = (double *)malloc(assets * bars * sizeof(*panel));
+    double *serial = (double *)malloc(assets * bars * sizeof(*serial));
+    double *parallel = (double *)malloc(assets * bars * sizeof(*parallel));
+    if (panel == NULL || serial == NULL || parallel == NULL) {
+        fprintf(stderr, "allocation failed\n");
+        return 1;
+    }
+    synthesize_panel(panel, assets, bars);
+
+    double t0 = now_seconds();
+    for (size_t a = 0; a < assets; ++a) {
+        run_one(which, &panel[a * bars], &serial[a * bars], bars);
+    }
+    double t_serial = now_seconds() - t0;
+    printf("Serial:   %8.3f s  (%llu assets, indicator=%s)\n", t_serial,
+           (unsigned long long)assets, ind_name);
+
+    /* The loop variable is declared outside the `for` and the bound is a plain
+     * variable: MSVC's OpenMP 2.0 rejects an in-init declaration or a cast in
+     * the condition (error C3015). */
+    long a;
+    long asset_count = (long)assets;
+    t0 = now_seconds();
+#ifdef _OPENMP
+#pragma omp parallel for schedule(static)
+#endif
+    for (a = 0; a < asset_count; ++a) {
+        run_one(which, &panel[(size_t)a * bars], &parallel[(size_t)a * bars], bars);
+    }
+    double t_parallel = now_seconds() - t0;
+    double denom = t_parallel > 1e-9 ? t_parallel : 1e-9;
+#ifdef _OPENMP
+    printf("Parallel: %8.3f s  (OpenMP, %d threads, speedup ~%.2fx)\n", t_parallel,
+           omp_get_max_threads(), t_serial / denom);
+#else
+    printf("Parallel: %8.3f s  (no OpenMP at build time — serial, speedup ~%.2fx)\n",
+           t_parallel, t_serial / denom);
+#endif
+
+    /* The parallel run must reproduce the serial results exactly. */
+    for (size_t i = 0; i < assets * bars; ++i) {
+        int both_nan = isnan(serial[i]) && isnan(parallel[i]);
+        if (!both_nan && serial[i] != parallel[i]) {
+            fprintf(stderr, "mismatch at %llu: serial=%g parallel=%g\n",
+                    (unsigned long long)i, serial[i], parallel[i]);
+            return 1;
+        }
+    }
+    printf("Parallel results match serial results — OK.\n");
+
+    free(panel);
+    free(serial);
+    free(parallel);
+    return 0;
+}

examples/c/strategy_bollinger_squeeze.c

@@ -0,0 +1,137 @@
+/* Strategy example: Bollinger-Squeeze breakout with ATR stop (Wickra C ABI).
+ *
+ * Enters long when the Bollinger Bandwidth has just printed a fresh 6-month low
+ * (the squeeze) and price closes above the upper band (the release). Exits when
+ * price closes below entry minus 2*ATR(14), or when the upper band trails back
+ * below the entry price (the squeeze has played out). 0.1% fees per trade. The
+ * C counterpart of `examples/rust/src/bin/strategy_bollinger_squeeze.rs`.
+ *
+ * Educational example. NOT a live trading recommendation. Uses the checked-in
+ * `examples/data/btcusdt-1d.csv` dataset because daily bars give an
+ * interpretable "6-month low" lookback (~180 bars).
+ *
+ * Build (after `cargo build -p wickra-c --release`):
+ *   cc examples/c/strategy_bollinger_squeeze.c -I bindings/c/include -L target/release -lwickra -lm -o strat_bb
+ */
+
+#define WICKRA_CSV_IMPL
+#define WICKRA_STRATEGY_IMPL
+#include "wickra.h"
+#include "wickra_csv.h"
+#include "wickra_strategy.h"
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#ifndef WICKRA_DATA_DIR
+#define WICKRA_DATA_DIR "../data"
+#endif
+
+#define FEE 0.001
+#define BB_PERIOD 20
+#define BB_K 2.0
+#define ATR_PERIOD 14
+#define ATR_STOP_MULT 2.0
+#define SQUEEZE_LOOKBACK 180 /* ~6 months of daily bars */
+
+int main(int argc, char **argv) {
+    const char *path = (argc > 1) ? argv[1] : WICKRA_DATA_DIR "/btcusdt-1d.csv";
+
+    WickraCandle *candles = NULL;
+    size_t n = wickra_load_csv(path, &candles);
+    if (n < SQUEEZE_LOOKBACK + BB_PERIOD) {
+        fprintf(stderr, "dataset has only %llu bars; need at least %d\n",
+                (unsigned long long)n, SQUEEZE_LOOKBACK + BB_PERIOD);
+        free(candles);
+        return 1;
+    }
+
+    struct BollingerBands *bb = wickra_bollinger_bands_new(BB_PERIOD, BB_K);
+    struct Atr *atr = wickra_atr_new(ATR_PERIOD);
+    double *trades = (double *)malloc(n * sizeof(*trades));
+    double *equity_curve = (double *)malloc(n * sizeof(*equity_curve));
+    /* Circular buffer of recent bandwidth values for the squeeze lookback. */
+    double bw_window[SQUEEZE_LOOKBACK];
+    size_t bw_len = 0, bw_head = 0;
+    if (bb == NULL || atr == NULL || trades == NULL || equity_curve == NULL) {
+        fprintf(stderr, "allocation failed\n");
+        return 1;
+    }
+
+    int in_position = 0;
+    double entry_price = 0.0, stop_level = 0.0;
+    size_t n_trades = 0;
+    double equity = 1.0;
+
+    for (size_t i = 0; i < n; ++i) {
+        const WickraCandle *c = &candles[i];
+        double price = c->close;
+        WickraBollingerOutput b;
+        int bb_ready = wickra_bollinger_bands_update(bb, price, &b);
+        double a = wickra_atr_update(atr, c->open, c->high, c->low, c->close,
+                                     c->volume, c->timestamp);
+
+        equity_curve[i] = in_position ? equity * (price / entry_price) : equity;
+
+        if (!bb_ready || !isfinite(a)) {
+            continue;
+        }
+
+        double bandwidth =
+            fabs(b.middle) > 1e-15 ? (b.upper - b.lower) / b.middle : NAN;
+        if (isfinite(bandwidth)) {
+            if (bw_len == SQUEEZE_LOOKBACK) {
+                bw_window[bw_head] = bandwidth;
+                bw_head = (bw_head + 1) % SQUEEZE_LOOKBACK;
+            } else {
+                bw_window[bw_len++] = bandwidth;
+            }
+        }
+
+        if (bw_len < SQUEEZE_LOOKBACK || !isfinite(bandwidth)) {
+            continue;
+        }
+        double min_bw = INFINITY;
+        for (size_t k = 0; k < bw_len; ++k) {
+            if (bw_window[k] < min_bw) {
+                min_bw = bw_window[k];
+            }
+        }
+
+        if (in_position) {
+            int stop_hit = price < stop_level;
+            int upper_collapse = b.upper < entry_price;
+            if (stop_hit || upper_collapse) {
+                double trade_ret = price / entry_price - 1.0;
+                trades[n_trades++] = trade_ret;
+                equity *= (1.0 + trade_ret) * (1.0 - FEE);
+                in_position = 0;
+            }
+        } else {
+            int is_new_low = fabs(bandwidth - min_bw) < 1e-12;
+            int breakout = price > b.upper;
+            if (is_new_low && breakout) {
+                entry_price = price;
+                stop_level = price - ATR_STOP_MULT * a;
+                equity *= 1.0 - FEE;
+                in_position = 1;
+            }
+        }
+    }
+    if (in_position) {
+        double trade_ret = candles[n - 1].close / entry_price - 1.0;
+        trades[n_trades++] = trade_ret;
+        equity *= (1.0 + trade_ret) * (1.0 - FEE);
+    }
+
+    wickra_print_summary("Bollinger Squeeze Breakout (1d, BTCUSDT)", candles[0].close,
+                         candles[n - 1].close, n, trades, n_trades, equity,
+                         equity_curve, n);
+
+    wickra_bollinger_bands_free(bb);
+    wickra_atr_free(atr);
+    free(trades);
+    free(equity_curve);
+    free(candles);
+    return 0;
+}

examples/c/strategy_macd_adx.c

@@ -0,0 +1,107 @@
+/* Strategy example: MACD crossover with ADX trend-strength filter (Wickra C ABI).
+ *
+ * Long-only trend follower. Entries fire when the MACD line crosses above the
+ * signal line while ADX(14) > 20 (a market with at least mild directional
+ * strength); exits on the opposite MACD crossover regardless of ADX. 0.1% fees
+ * per trade. The C counterpart of `examples/rust/src/bin/strategy_macd_adx.rs`.
+ *
+ * The ADX filter is the point: pure MACD on sideways markets chops in and out;
+ * gating entries on directional strength cuts the worst losing streak.
+ *
+ * Educational example. NOT a live trading recommendation. Uses the checked-in
+ * `examples/data/btcusdt-1h.csv` dataset.
+ *
+ * Build (after `cargo build -p wickra-c --release`):
+ *   cc examples/c/strategy_macd_adx.c -I bindings/c/include -L target/release -lwickra -lm -o strat_macd
+ */
+
+#define WICKRA_CSV_IMPL
+#define WICKRA_STRATEGY_IMPL
+#include "wickra.h"
+#include "wickra_csv.h"
+#include "wickra_strategy.h"
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#ifndef WICKRA_DATA_DIR
+#define WICKRA_DATA_DIR "../data"
+#endif
+
+#define FEE 0.001
+#define ADX_FLOOR 20.0
+
+int main(int argc, char **argv) {
+    const char *path = (argc > 1) ? argv[1] : WICKRA_DATA_DIR "/btcusdt-1h.csv";
+
+    WickraCandle *candles = NULL;
+    size_t n = wickra_load_csv(path, &candles);
+    if (n == 0) {
+        fprintf(stderr, "CSV is empty: %s\n", path);
+        return 1;
+    }
+
+    struct MacdIndicator *macd = wickra_macd_indicator_new(12, 26, 9);
+    struct Adx *adx = wickra_adx_new(14);
+    double *trades = (double *)malloc(n * sizeof(*trades));
+    double *equity_curve = (double *)malloc(n * sizeof(*equity_curve));
+    if (macd == NULL || adx == NULL || trades == NULL || equity_curve == NULL) {
+        fprintf(stderr, "allocation failed\n");
+        return 1;
+    }
+
+    int in_position = 0;
+    double entry_price = 0.0;
+    size_t n_trades = 0;
+    double equity = 1.0;
+    /* Previous histogram sign to detect MACD-line crossovers: -1 unset, 0/1 sign. */
+    int prev_hist_sign = -1;
+
+    for (size_t i = 0; i < n; ++i) {
+        const WickraCandle *c = &candles[i];
+        double price = c->close;
+        WickraMacdOutput m;
+        int macd_ready = wickra_macd_indicator_update(macd, price, &m);
+        WickraAdxOutput a;
+        int adx_ready = wickra_adx_update(adx, c->open, c->high, c->low, c->close,
+                                          c->volume, c->timestamp, &a);
+
+        equity_curve[i] = in_position ? equity * (price / entry_price) : equity;
+
+        if (!macd_ready || !adx_ready) {
+            continue;
+        }
+
+        int hist_sign = m.histogram > 0.0 ? 1 : 0;
+        int cross_up = prev_hist_sign == 0 && hist_sign == 1;
+        int cross_down = prev_hist_sign == 1 && hist_sign == 0;
+        prev_hist_sign = hist_sign;
+
+        if (!in_position && cross_up && a.adx > ADX_FLOOR) {
+            entry_price = price;
+            equity *= 1.0 - FEE;
+            in_position = 1;
+        } else if (in_position && cross_down) {
+            double trade_ret = price / entry_price - 1.0;
+            trades[n_trades++] = trade_ret;
+            equity *= (1.0 + trade_ret) * (1.0 - FEE);
+            in_position = 0;
+        }
+    }
+    if (in_position) {
+        double trade_ret = candles[n - 1].close / entry_price - 1.0;
+        trades[n_trades++] = trade_ret;
+        equity *= (1.0 + trade_ret) * (1.0 - FEE);
+    }
+
+    wickra_print_summary("MACD + ADX Trend Filter (1h, BTCUSDT)", candles[0].close,
+                         candles[n - 1].close, n, trades, n_trades, equity,
+                         equity_curve, n);
+
+    wickra_macd_indicator_free(macd);
+    wickra_adx_free(adx);
+    free(trades);
+    free(equity_curve);
+    free(candles);
+    return 0;
+}

examples/c/strategy_rsi_mean_reversion.c

@@ -0,0 +1,95 @@
+/* Strategy example: RSI mean-reversion on hourly BTCUSDT data (Wickra C ABI).
+ *
+ * Goes long when RSI(14) crosses below 30 (oversold), exits when RSI crosses
+ * above 70 (overbought). Position is binary (full-in / full-out), fees are 0.1%
+ * per trade (Binance maker tier), no stop-loss. The C counterpart of
+ * `examples/rust/src/bin/strategy_rsi_mean_reversion.rs`.
+ *
+ * Educational example. NOT a recommended trading strategy — the point is to
+ * show how a Wickra streaming indicator wires into a signal -> fill -> PnL ->
+ * equity loop. Uses the checked-in `examples/data/btcusdt-1h.csv` dataset.
+ *
+ * Build (after `cargo build -p wickra-c --release`):
+ *   cc examples/c/strategy_rsi_mean_reversion.c -I bindings/c/include -L target/release -lwickra -lm -o strat_rsi
+ */
+
+#define WICKRA_CSV_IMPL
+#define WICKRA_STRATEGY_IMPL
+#include "wickra.h"
+#include "wickra_csv.h"
+#include "wickra_strategy.h"
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#ifndef WICKRA_DATA_DIR
+#define WICKRA_DATA_DIR "../data"
+#endif
+
+#define FEE 0.001
+#define RSI_PERIOD 14
+#define OVERSOLD 30.0
+#define OVERBOUGHT 70.0
+
+int main(int argc, char **argv) {
+    const char *path = (argc > 1) ? argv[1] : WICKRA_DATA_DIR "/btcusdt-1h.csv";
+
+    WickraCandle *candles = NULL;
+    size_t n = wickra_load_csv(path, &candles);
+    if (n < RSI_PERIOD * 4) {
+        fprintf(stderr, "dataset too small: %llu\n", (unsigned long long)n);
+        free(candles);
+        return 1;
+    }
+
+    struct Rsi *rsi = wickra_rsi_new(RSI_PERIOD);
+    double *trades = (double *)malloc(n * sizeof(*trades));
+    double *equity_curve = (double *)malloc(n * sizeof(*equity_curve));
+    if (rsi == NULL || trades == NULL || equity_curve == NULL) {
+        fprintf(stderr, "allocation failed\n");
+        return 1;
+    }
+
+    int in_position = 0;
+    double entry_price = 0.0;
+    size_t n_trades = 0;
+    double equity = 1.0;
+
+    for (size_t i = 0; i < n; ++i) {
+        double price = candles[i].close;
+        double r = wickra_rsi_update(rsi, price);
+
+        /* Mark-to-market so the equity curve moves bar-by-bar between trades. */
+        equity_curve[i] = in_position ? equity * (price / entry_price) : equity;
+
+        if (!isfinite(r)) {
+            continue;
+        }
+        if (!in_position && r < OVERSOLD) {
+            entry_price = price;
+            equity *= 1.0 - FEE;
+            in_position = 1;
+        } else if (in_position && r > OVERBOUGHT) {
+            double trade_ret = price / entry_price - 1.0;
+            trades[n_trades++] = trade_ret;
+            equity *= (1.0 + trade_ret) * (1.0 - FEE);
+            in_position = 0;
+        }
+    }
+    /* Close any still-open trade at the last bar so metrics include it. */
+    if (in_position) {
+        double trade_ret = candles[n - 1].close / entry_price - 1.0;
+        trades[n_trades++] = trade_ret;
+        equity *= (1.0 + trade_ret) * (1.0 - FEE);
+    }
+
+    wickra_print_summary("RSI Mean-Reversion (1h, BTCUSDT)", candles[0].close,
+                         candles[n - 1].close, n, trades, n_trades, equity,
+                         equity_curve, n);
+
+    wickra_rsi_free(rsi);
+    free(trades);
+    free(equity_curve);
+    free(candles);
+    return 0;
+}

examples/c/streaming.c

@@ -1,36 +1,110 @@
-/* Streaming usage example for the Wickra C ABI.
+/* Streaming indicators with the Wickra C ABI.
  *
- * The same five-function shape (new / update / batch / reset / free) drives every
+ * Feeds a synthetic price series through several indicators tick by tick — the
- * scalar indicator. Here an EMA consumes a live tick stream one value at a time;
+ * same O(1)-per-update model a live trading bot would use — and prints a status
- * `update` is O(1) per tick and returns NaN until the indicator has warmed up.
+ * line once every indicator has warmed up. The C counterpart of
+ * `examples/rust/src/bin/streaming.rs`, `examples/python/streaming.py` and
+ * `examples/node/streaming.js`, using the same seeded LCG so a side-by-side run
+ * produces visibly comparable streams.
  *
  * Build (after `cargo build -p wickra-c --release`):
  *   cc examples/c/streaming.c -I bindings/c/include -L target/release -lwickra -lm -o streaming
  */
 
 #include "wickra.h"
+#include <math.h>
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 
-int main(void) {
+#define DEFAULT_TICKS 120
-    struct Ema *ema = wickra_ema_new(5);
+
-    if (ema == NULL) {
+/* Deterministic synthetic series matching the sibling examples' seeded LCG. */
-        fprintf(stderr, "failed to create EMA\n");
+static void make_series(double *prices, size_t n) {
+    uint64_t seed = 1234567u;
+    for (size_t t = 0; t < n; ++t) {
+        seed = (seed * 1103515245u + 12345u) & 0x7FFFFFFFu;
+        double rnd = (double)seed / (double)0x7FFFFFFFu;
+        double tf = (double)t;
+        prices[t] = 100.0 + tf * 0.05 + sin(tf * 0.07) * 8.0 + cos(tf * 0.21) * 3.0 +
+                    (rnd - 0.5);
+    }
+}
+
+/* Format an indicator value, rendering warmup (NaN) as a dashed placeholder. */
+static void fmt(char *buf, size_t buflen, double v) {
+    if (isfinite(v)) {
+        snprintf(buf, buflen, "%7.2f", v);
+    } else {
+        snprintf(buf, buflen, "  --   ");
+    }
+}
+
+int main(int argc, char **argv) {
+    size_t ticks = DEFAULT_TICKS;
+    if (argc == 3 && strcmp(argv[1], "--ticks") == 0) {
+        long parsed = strtol(argv[2], NULL, 10);
+        if (parsed <= 0) {
+            fprintf(stderr, "--ticks must be positive\n");
+            return 1;
+        }
+        ticks = (size_t)parsed;
+    } else if (argc != 1) {
+        fprintf(stderr, "usage: streaming [--ticks N]\n");
         return 1;
     }
 
-    const double prices[] = {10.0, 10.5, 11.0, 10.8, 11.2, 11.5, 11.3, 11.8};
+    struct Sma *sma = wickra_sma_new(20);
-    const size_t n = sizeof(prices) / sizeof(prices[0]);
+    struct Ema *ema = wickra_ema_new(20);
+    struct Rsi *rsi = wickra_rsi_new(14);
+    struct MacdIndicator *macd = wickra_macd_indicator_new(12, 26, 9);
+    double *prices = (double *)malloc(ticks * sizeof(*prices));
+    if (sma == NULL || ema == NULL || rsi == NULL || macd == NULL || prices == NULL) {
+        fprintf(stderr, "allocation failed\n");
+        return 1;
+    }
+    make_series(prices, ticks);
 
-    printf("EMA(5) streaming:\n");
+    printf("Wickra streaming indicator demo (C)\n\n");
-    for (size_t i = 0; i < n; ++i) {
+
-        double value = wickra_ema_update(ema, prices[i]);
+    size_t signals = 0;
-        if (value != value) { /* NaN during warmup */
+    for (size_t t = 0; t < ticks; ++t) {
-            printf("  tick %zu  price %.2f  ->  (warming up)\n", i, prices[i]);
+        double price = prices[t];
-        } else {
+        double sv = wickra_sma_update(sma, price);
-            printf("  tick %zu  price %.2f  ->  %.4f\n", i, prices[i], value);
+        double ev = wickra_ema_update(ema, price);
+        double rv = wickra_rsi_update(rsi, price);
+        WickraMacdOutput m;
+        int macd_ready = wickra_macd_indicator_update(macd, price, &m);
+
+        /* Only act once every indicator has produced a value. */
+        if (!isfinite(sv) || !isfinite(ev) || !isfinite(rv) || !macd_ready) {
+            continue;
         }
+
+        int overbought = rv > 70.0 && m.histogram < 0.0;
+        int oversold = rv < 30.0 && m.histogram > 0.0;
+        const char *tag = overbought ? "SELL?" : (oversold ? "BUY? " : "     ");
+        if (overbought || oversold) {
+            signals++;
+        }
+
+        char b_price[16], b_sma[16], b_ema[16], b_rsi[16], b_hist[16];
+        fmt(b_price, sizeof(b_price), price);
+        fmt(b_sma, sizeof(b_sma), sv);
+        fmt(b_ema, sizeof(b_ema), ev);
+        fmt(b_rsi, sizeof(b_rsi), rv);
+        fmt(b_hist, sizeof(b_hist), m.histogram);
+        printf("t=%3llu  price=%s  sma=%s  ema=%s  rsi=%s  macd_hist=%s  %s\n",
+               (unsigned long long)t, b_price, b_sma, b_ema, b_rsi, b_hist, tag);
     }
 
+    printf("\nDone — %llu candidate signal(s) over %llu ticks.\n",
+           (unsigned long long)signals, (unsigned long long)ticks);
+
+    wickra_sma_free(sma);
     wickra_ema_free(ema);
+    wickra_rsi_free(rsi);
+    wickra_macd_indicator_free(macd);
+    free(prices);
     return 0;
 }

examples/c/wickra_csv.h

@@ -0,0 +1,90 @@
+/* Shared OHLCV CSV loader for the Wickra C examples.
+ *
+ * The C ABI exposes only the indicators, not the wickra-data IO layer, so the
+ * examples read CSV themselves. This header-only helper is the C counterpart of
+ * `wickra_data::csv::CandleReader` used by the Rust examples: it parses the
+ * standard `timestamp,open,high,low,close,volume` files shipped under
+ * `examples/data/`.
+ *
+ * Header-only: define WICKRA_CSV_IMPL in exactly one translation unit (each
+ * example is a single .c file, so it just defines it before including this).
+ */
+#ifndef WICKRA_CSV_H
+#define WICKRA_CSV_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+typedef struct WickraCandle {
+    int64_t timestamp;
+    double open;
+    double high;
+    double low;
+    double close;
+    double volume;
+} WickraCandle;
+
+/* Load an OHLCV CSV into a malloc'd array. Returns the candle count and stores
+ * the array in *out (caller frees with free()). Returns 0 and leaves *out NULL
+ * on any error (missing file, no parseable rows). A leading header line whose
+ * first field is non-numeric is skipped. */
+size_t wickra_load_csv(const char *path, WickraCandle **out);
+
+#ifdef WICKRA_CSV_IMPL
+
+#include <stdio.h>
+#include <stdlib.h>
+
+size_t wickra_load_csv(const char *path, WickraCandle **out) {
+    *out = NULL;
+    FILE *f = fopen(path, "r");
+    if (f == NULL) {
+        fprintf(stderr, "wickra_load_csv: cannot open %s\n", path);
+        return 0;
+    }
+
+    size_t cap = 1024;
+    size_t n = 0;
+    WickraCandle *rows = (WickraCandle *)malloc(cap * sizeof(*rows));
+    if (rows == NULL) {
+        fclose(f);
+        return 0;
+    }
+
+    char line[512];
+    while (fgets(line, (int)sizeof(line), f) != NULL) {
+        WickraCandle c;
+        long long ts = 0;
+        /* sscanf returns the number of fields successfully matched. A header
+         * row ("timestamp,...") matches 0 and is skipped. */
+        int matched = sscanf(line, "%lld,%lf,%lf,%lf,%lf,%lf", &ts, &c.open,
+                             &c.high, &c.low, &c.close, &c.volume);
+        if (matched != 6) {
+            continue;
+        }
+        c.timestamp = (int64_t)ts;
+
+        if (n == cap) {
+            cap *= 2;
+            WickraCandle *grown = (WickraCandle *)realloc(rows, cap * sizeof(*rows));
+            if (grown == NULL) {
+                free(rows);
+                fclose(f);
+                return 0;
+            }
+            rows = grown;
+        }
+        rows[n++] = c;
+    }
+    fclose(f);
+
+    if (n == 0) {
+        free(rows);
+        return 0;
+    }
+    *out = rows;
+    return n;
+}
+
+#endif /* WICKRA_CSV_IMPL */
+#endif /* WICKRA_CSV_H */

examples/c/wickra_strategy.h

@@ -0,0 +1,92 @@
+/* Shared equity-curve summary for the Wickra C strategy examples.
+ *
+ * The Rust strategy examples repeat their `print_summary` per file; in C the
+ * presentation is factored into this header so each strategy .c file stays
+ * focused on its signal logic. Pure reporting — no indicator state.
+ *
+ * Header-only: define WICKRA_STRATEGY_IMPL in exactly one translation unit.
+ */
+#ifndef WICKRA_STRATEGY_H
+#define WICKRA_STRATEGY_H
+
+#include <stddef.h>
+
+/* Print a one-screen summary of a strategy run: returns vs buy & hold, trade
+ * win/loss counts, max drawdown, per-trade Sharpe, best/worst trade. */
+void wickra_print_summary(const char *name, double first_price, double last_price,
+                          size_t bars, const double *closed_trades, size_t n_trades,
+                          double final_equity, const double *equity_curve,
+                          size_t n_curve);
+
+#ifdef WICKRA_STRATEGY_IMPL
+
+#include <math.h>
+#include <stdio.h>
+
+void wickra_print_summary(const char *name, double first_price, double last_price,
+                          size_t bars, const double *closed_trades, size_t n_trades,
+                          double final_equity, const double *equity_curve,
+                          size_t n_curve) {
+    double buy_hold = last_price / first_price;
+    double strat_return = final_equity - 1.0;
+    double bh_return = buy_hold - 1.0;
+
+    size_t wins = 0, losses = 0;
+    double best = -INFINITY, worst = INFINITY;
+    double sum_ret = 0.0, sum_sq = 0.0;
+    for (size_t i = 0; i < n_trades; ++i) {
+        double r = closed_trades[i];
+        if (r > 0.0) {
+            wins++;
+        } else if (r < 0.0) {
+            losses++;
+        }
+        if (r > best) {
+            best = r;
+        }
+        if (r < worst) {
+            worst = r;
+        }
+        sum_ret += r;
+        sum_sq += r * r;
+    }
+    double n = (double)n_trades;
+    double mean_ret = n > 0.0 ? sum_ret / n : 0.0;
+    double var_ret = n > 1.0 ? (sum_sq - n * mean_ret * mean_ret) / (n - 1.0) : 0.0;
+    double sharpe = var_ret > 0.0 ? mean_ret / sqrt(var_ret) : 0.0;
+    if (n_trades == 0) {
+        best = 0.0;
+        worst = 0.0;
+    }
+
+    double peak = n_curve > 0 ? equity_curve[0] : 1.0;
+    double max_dd = 0.0;
+    for (size_t i = 0; i < n_curve; ++i) {
+        if (equity_curve[i] > peak) {
+            peak = equity_curve[i];
+        }
+        double dd = (peak - equity_curve[i]) / peak;
+        if (dd > max_dd) {
+            max_dd = dd;
+        }
+    }
+
+    printf("=== %s ===\n", name);
+    printf("Bars:                  %llu\n", (unsigned long long)bars);
+    printf("Trades:                %llu (W%llu / L%llu)\n", (unsigned long long)n_trades,
+           (unsigned long long)wins, (unsigned long long)losses);
+    printf("Strategy return:       %+.2f%%\n", strat_return * 100.0);
+    printf("Buy & Hold return:     %+.2f%%\n", bh_return * 100.0);
+    printf("Excess over BH:        %+.2f%%\n", (strat_return - bh_return) * 100.0);
+    printf("Max drawdown:          %.2f%%\n", max_dd * 100.0);
+    printf("Per-trade Sharpe:      %.2f  (mean %+.4f, stddev %.4f)\n", sharpe,
+           mean_ret, sqrt(var_ret));
+    printf("Best / worst trade:    %+.2f%% / %+.2f%%\n", best * 100.0, worst * 100.0);
+    printf("\n");
+    printf("NOTE: Educational example — fees, slippage, funding costs and tax "
+           "effects are simplified or omitted. Past performance is not indicative "
+           "of future results.\n");
+}
+
+#endif /* WICKRA_STRATEGY_IMPL */
+#endif /* WICKRA_STRATEGY_H */