Ticket #18348: foo.c

#include <threads.h>
#include <stdlib.h>

static once_flag a_once = ONCE_FLAG_INIT;

static int a;

static void
a_init (void)
{
  a = 42;
}

int
main ()
{
  call_once (&a_once, a_init);

  if (!(a == 42))
    abort ();

  return 0;
}