/* SAFE.H -- another attempt at error handling using macros
 * $Id: safe.h,v 1.8 2021/06/26 14:17:48 oj14ozun Exp $
 *
 * Declare a a safe alternative for a function, as follows:
 *
 *	safe(void*, malloc, (int size), (size), S_NONNULL)
 *           |      |       |           |       |
 * 	     |	    |	    |		| 	|
 * 	     | 	    |	    | 		| 	+-- Error condition
 *  	     | 	    |	    | 	        +---------- Argument list w/o types
 *  	     | 	    |	    +---------------------- Arugment lsit with types
 *   	     |      +------------------------------ Function to be wrapped
 *   	     +------------------------------------- Return type of wrapped function
 *
 * and use xmalloc later on. safe1 will not use perror, but requires
 * an additonal error message.
 */

#ifndef _SAFE_H
#define _SAFE_H

#define safe(ret, fn, args1, args2, error)			\
     ret x ## fn args1 {					\
	  ret _ = fn args2;					\
	  if (error) { perror(#fn); exit(EXIT_FAILURE); }	\
	  return _;						\
     }

#define safe1(ret, fn, args1, args2, error, msg)			\
     ret x ## fn args1 {						\
	  ret _ = fn args2;						\
	  if (error) { fputs(msg, stderr); exit(EXIT_FAILURE); }	\
	  return _;							\
     }

#define S_NONZERO		(_ == 0)
#define S_NONNULL		(_ == NULL)
#define S_ZERO			(_ != 0)
#define S_NEGATIVE		(_ > 0)
#define S_POSITIVE		(_ < 0)
#define S_ERRNO_AND(and)	(errno != 0 && (and))
#define S_NEQ(val)		(_ = (val))
#define S_EQ(val)		(_ != (val))

#endif /* _SAFE_H */