Ticket #105 (NULL checks)

[Joshua Juran]

On Dec 31, 2008, at 8:57 AM, kjstol wrote:

> On Wed, Dec 31, 2008 at 5:03 PM, Mark Glines <mark at glines.org> wrote:
>
> > I'm pretty sure assert() is a C library function.
>
> I think it's a C #define'd macro, not a function, which is not  
> expanded if you set the right debug #define
> (don't know details by heart).

C's assert() must be implemented as a macro, so the failure report  
can make use of the string containing the assertion itself (see  
'#cond' below) as well as __FILE__ and __LINE__.

Macros are always expanded, to whatever you define them to.  The  
trick is that you can define them differently based on other macros  
set by the build manager.

I defined my own ASSERT() macro (which has less surprising semantics  
than assert() and helps avoid warnings):

	#if TARGET_CONFIG_DEBUGGING
		
		#define ASSERT( cond )  if ( !(cond) )  
ReportAssertionFailureAndAbort( #cond,  __FILE__, __LINE__ ); else 0
		
	#else
		
		#define ASSERT( cond )  if ( 0 ) (void) !(cond); else 0
		
	#endif

If cond is known to be non-NULL, then the debugging assertion will be  
stripped out in optimization just as handily as the non-debug one.

Josh