hello gcc 4.2.1 C preprocessor question, any clues are welcome;

[mm w <0xcafefeed at gmail dot com>]

gcc -v
Using built-in specs.
Target: i686-apple-darwin10
Configured with: /var/tmp/gcc/gcc-5659~1/src/configure
--disable-checking --enable-werror --prefix=/usr --mandir=/share/man
--enable-languages=c,objc,c++,obj-c++
--program-transform-name=/^[cg][^.-]*$/s/$/-4.2/
--with-slibdir=/usr/lib --build=i686-apple-darwin10
--program-prefix=i686-apple-darwin10- --host=x86_64-apple-darwin10
--target=i686-apple-darwin10 --with-gxx-include-dir=/include/c++/4.2.1
Thread model: posix
gcc version 4.2.1 (Apple Inc. build 5659)


-- BEGIN header OSAtomicLock.h

#ifndef OSATOMICLOCK_H
#define OSATOMICLOCK_H

#if !defined(OS_INLINE)
    #if defined(__GNUC__) && (__GNUC__ == 4) && !defined(DEBUG)
        #define OS_INLINE static __inline__ __attribute__((always_inline))
    #elif defined(__GNUC__)
        #define OS_INLINE static __inline__
    #elif defined(__cplusplus)
		#define OS_INLINE static inline
    #elif defined(_MSC_VER)
        #define OS_INLINE static __inline
    #elif defined(__WIN32__)
		#define OS_INLINE static __inline__
    #endif
#endif

#if defined(__WIN32__)
	typedef __int32 OSAtomicLockLock;
	#define OSAtomicLockInit 0
	D_INLINE void __OSAtomicLockLock(volatile OSAtomicLock *LOCK) {
    	while (InterlockedCompareExchange((LONG volatile *)LOCK, ~0, 0) != 0) {
			Sleep(0);
    	}
	}	
	D_INLINE void __OSAtomicLockUnlock(volatile OSAtomicLock *LOCK) {
		MemoryBarrier();
		*LOCK = 0;
	}
#elif defined(__APPLE__)
	#include <libkern/OSAtomic.h>
	typedef OSSpinLock OSAtomicLock;
	#define OSAtomicLockInit OS_SPINLOCK_INIT
	#define __OSAtomicLockLock(LOCK) ({ \
		OSAtomicLock *lck_p = (LOCK); \
		OSAtomicLock lck_v = *lck_p; \
		if (0 != lck_v && ~0 != lck_v && (uintptr_t)lck_p != (uintptr_t)lck_v) { } \
		OSSpinLockLock(lck_p); \
	})	
	#define __OSAtomicLockUnlock(LOCK) ({ \
		OSAtomicLock *lck_p = (LOCK); \
		OSAtomicLock lck_v = *lck_p; \
		if (~0 != lck_v && (uintptr_t)lck_p != (uintptr_t)lck_v) { } \
		OSSpinLockUnlock(lck_p); \
	})
#else // means posix
	#define _MULTI_THREADED
	#include <pthread.h>
	#if defined(__linux__)
		#define OSAtomicLockInit PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP
	#else
		#define OSAtomicLockInit PTHREAD_MUTEX_INITIALIZER
	#endif
	typedef pthread_mutex_t OSAtomicLock;
	#define __OSAtomicLockLock(LOCK) ({ \
		OSAtomicLock *lck_p = (LOCK); \
		pthread_mutex_lock(lck_p); \
	})
	#define  __OSAtomicLockUnlock(LOCK) ({ \
		OSAtomicLock *lck_p = (LOCK); \
		pthread_mutex_unlock(lck_p); \
	})
#endif

#define OSAtomicLockInitialize(LOCK) (LOCK = OSAtomicLockInit)
#define OSAtomicLockLock(LOCK) __OSAtomicLockLock(LOCK)
#define OSAtomicLockUnlock(LOCK) __OSAtomicLockUnlock(LOCK)

#define OSAtomicAutoLock(LOCK, BLOCK) \
	OSAtomicLockLock(LOCK); \
	BLOCK \
	OSAtomicLockUnlock(LOCK);

#endif // OSATOMICLOCK_H

/* HOWTO
	static OSAtomicLock __myGlobalLock = OSAtomicLockInit;
	void mylocalfunc()
	{
		OSAtomicLockLock(&__myGlobalLock);
		//do stuff
		OSAtomicLockUnlock(&__myGlobalLock);
	}
*/

-- END header OSAtomicLock.h


-- BEGIN test1.c

#include <stdio.h>
#include "OSAtomicLock.h"

static OSAtomicLock __myGlobalLock = OSAtomicLockInit;

int main (int argc, const char** argv)
{
	OSAtomicLockLock(&__myGlobalLock);
	fprintf(stderr,"hello\n");
	OSAtomicLockLock(&__myGlobalLock);
	return 0;
}

-- END test1.c

-- BEGIN test2.c

#include <stdio.h>
#include "OSAtomicLock.h"

static OSAtomicLock __myGlobalLock = OSAtomicLockInit;

int main (int argc, const char** argv)
{
	OSAtomicAutoLock
	(
		&__myGlobalLock,
		fprintf(stderr,"hello\n");
	)
	return 0;
}

-- END test2.c

and the main thread blocked;

-- BEGIN test1.S

L2:
	...
	movq	-24(%rbp), %rdi
	call	_OSSpinLockUnlock
	movl	$0, %eax
	leave
	ret

-- END test1.S

-- BEGIN test2.S


L2:
	...
	je	L5
L5:
	movq	-24(%rbp), %rdi
	call	_OSSpinLockLock
	movl	$0, %eax
	leave
	ret

-- END test2.S

and the main thread will bell;

Best Regards