assert(3X)							    assert(3X)

NAME    [Toc]    [Back]

     assert - verify program assertion

SYNOPSIS    [Toc]    [Back]

     #include <assert.h>

     void assert (int expression);

DESCRIPTION    [Toc]    [Back]

     This macro	is useful for putting diagnostics into programs.  When it is
     executed, if expression is	false (zero), assert prints

	  Assertion failed: expression,	file xyz, line nnn

     on	the standard error output and aborts.  In the error message, xyz is
     the name of the source file and nnn the source line number	of the assert
     statement.	 The latter are	respectively the values	of the preprocessor
     macros __FILE__ and __LINE__.

     Compiling with the	preprocessor option -DNDEBUG [see cc(1)], or with the
     preprocessor control statement #define NDEBUG ahead of the	#include
     <assert.h>	statement, will	stop assertions	from being compiled into the
     program.

SEE ALSO    [Toc]    [Back]

     cc(1), abort(3C)

NOTES    [Toc]    [Back]

     Since assert is implemented as a macro, the expression may	not contain
     any string	literals.


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