libs-base/config/config.initialize.m

/* Test whether Objective-C runtime +initialize support is thread-safe
 */

#include "objc-common.g"
#include <pthread.h>

static unsigned	initialize_entered = 0;
static unsigned	initialize_exited = 0;
static unsigned	class_entered = 0;
static BOOL	may_proceed = NO;

@interface	MyClass : NSObject
@end
@implementation	MyClass
+ (void) initialize
{
  initialize_entered++;
  while (NO == may_proceed)
    sleep(1);
  initialize_exited++;
}
+ (Class) class
{
  class_entered++;
  return self;
}
@end

static void test(void *arg)
{
  [MyClass class];
}

int
main()
{
  pthread_t     t1;
  pthread_t     t2;

  if (0 == pthread_create(&t1, 0, test, 0))
    {
      unsigned	counter = 0;

      while (0 == initialize_entered && counter++ < 3)
	{
	  sleep(1);
	}
      if (0 == initialize_entered)
	{
	  fprintf(stderr, "Failed to initialize\n");
	  return 1;
	}
      if (0 == pthread_create(&t1, 0, test, 0))
        {
	  sleep(1);
	  if (class_entered > 0)
	    {
	      fprintf(stderr, "class entered prematurely\n");
	      return 1;
	    }
	  may_proceed = YES;
	  sleep(1);
	  if (2 == class_entered)
	    {
	      return 0;	// OK
	    }
	  fprintf(stderr, "problem with initialize\n");
	  return 1;
	}
      else
	{
	  fprintf(stderr, "failed to create t2\n");
	  return 1;
	}
    }
  else
    {
      fprintf(stderr, "failed to create t1\n");
      return 1;
    }
}