coroutine

The simpliest implementation of coroutine in C. It is inspired from an article of Simon Tatham here.

This repository contains tests but all you need is the header file in the include directory.

Basic usage:

#include <stdio.h>
#include <coroutine.h>

static int coroutine(coroutine_context_t **context, int offset) {
  ///////////////////////////////////
  /// The "persistent" data
  ///////////////////////////////////

  COROUTINE_CONTEXT_BEGIN();
  int count;
  COROUTINE_CONTEXT_END(context);

  ///////////////////////////////////

  COROUTINE_BEGIN();

  COROUTINE_YIELD(offset + 1);
  if (coroutine_context->count < 2) {
    ++coroutine_context->count;
    COROUTINE_YIELD_AND_KEEP_LAST_ENTRYPOINT(offset + 2);
  }
  COROUTINE_YIELD(offset + 3);

  COROUTINE_FINISH();

  return offset + 4;
}

int main(void) {
  coroutine_context_t *context = NULL;

  printf("=====================\n");
  int offset = 3;
  do {
  	printf("%d\n", coroutine(&context, offset));
  } while (context);
  printf("=====================\n");

  return 0;
}

This should output this:

=====================
4
5
5
6
7
=====================

Look at the tests to see more usages.