Function do_thread

wasm2c/examples/threads/threads.c:61–105

}

void* do_thread(void* arg) {
  int param;
  memcpy(&param, arg, sizeof(int));

  /* Initialize the per-thread context for the Wasm runtime (in
     practice, this allocates and installs an alternate stack for
     catching segfaults caused by stack exhaustion or out-of-bounds
     memory access). */
  wasm_rt_init_thread();

  /* Instantiate the Wasm module. */
  w2c_sample inst;
  wasm2c_sample_instantiate(&inst);

  /* Expect a stack-exhaustion trap. (N.B. in a pthreads-created stack, Linux's
     segfault for stack overflow appears the same as one for memory OOB. This is
     similar to the behavior of macOS when exhausting a non-pthreads stack. */
  wasm_rt_trap_t code = wasm_rt_impl_try();
  if (code != 0) {
    if (code == WASM_RT_TRAP_OOB || code == WASM_RT_TRAP_EXHAUSTION) {
      /* Trap arrived as expected. Now call the "real" function. */
      int returnval = w2c_sample_multiplyby3(&inst, param);
      memcpy(arg, &returnval, sizeof(int));

      /* Free the module instance. */
      wasm2c_sample_free(&inst);

      /* Free the per-thread runtime context. */
      wasm_rt_free_thread();

      return arg;
    } else {
      fprintf(stderr, "Expected OOB or exhaustion trap but got %s\n",
              wasm_rt_strerror(code));
      return NULL;
    }
  }

  /* Call the stack-overflow function. Expect a trap back to above. */
  w2c_sample_stackoverflow(&inst);

  /* If no trap... */
  fprintf(stderr, "Expected trap but did not get one\n");
  return NULL;
}