hello.c

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/* -*- C -*-
 * Serene programming language
 * Copyright (C) 2019-2026 Sameer Rahmani <[email protected]>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
 
// Hello world for an external program that links libserene.runtime built with
// -Dwith-serene=disabled. It uses only the substrate: the memory manager, the
// engine/context, and the fiber subsystem. No value model, no LLVM.
 
#include <stdio.h>
 
#include "serene/rt/context.h"
#include "serene/rt/engine.h"
#include "serene/rt/fiber.h"
#include "serene/rt/mm/interface.h"
 
// A fiber result must be non-null. This sentinel stands in for "no value".
static int ok;
 
static srn_fiber_result_t say_hello(srn_context_t *ctx, void *arg) {
  (void)ctx;
  (void)arg;
  printf("hello from a Serene fiber (substrate runtime)\n");
  return &ok;
}
 
int main(void) {
  srn_mm_t *mm = srn_mm_init();
  srn_engine_t *engine = srn_engine_make(mm);
  srn_context_t *ctx = srn_context_make(engine);
  srn_scheduler_t *sched = engine->scheduler;
 
  (void)srn_fiber_make(ctx, sched, say_hello, NULL, 0);
  srn_sched_run(sched, 1);
 
  // Tear the engine (hence the scheduler) down before releasing the context the
  // fibers were allocated from.
  srn_engine_shutdown(engine);
  srn_context_release(ctx);
  srn_mm_shutdown(mm);
  return 0;
}