#ifndef	NDEBUG
#define	_assert(ex)	{if (!(ex)){fprintf(stderr,"Assertion failed: file %s, line %d\n", __FILE__, __LINE__);exit(1);}}
#define	assert(ex)	{if (!(ex)){fprintf(stderr,"Assertion failed: file %s, line %d\n", __FILE__, __LINE__);exit(1);}}
#else
#define	_assert(ex)	;
#define	assert(ex)	;
#endif