FreeBSD Man Pages

assert(3)

NAME

     assert -- expression verification macro

SYNOPSIS

     #include <assert.h>

     assert(expression);

DESCRIPTION

     The assert() macro tests the given expression and if it is false, the
     calling process is terminated.  A diagnostic message is written to stderr
     and the function abort(3) is called, effectively terminating the program.

     If expression is true, the assert() macro does nothing.

     The assert() macro may be removed at compile time by defining NDEBUG as a
     macro (e.g., by using the cc(1) option -DNDEBUG).

EXAMPLES

     The assertion:

	   assert(1 == 0);

     generates a diagnostic message similar to the following:

	   Assertion failed: (1 == 0), function main, file assertion.c, line
	   100.

SEE ALSO

     abort(3)

STANDARDS

     The assert() macro conforms to ISO/IEC 9899:1999 (``ISO C99'').

HISTORY

     An assert macro appeared in Version 6 AT&T UNIX.

FreeBSD 5.4		       January 26, 1999 		   FreeBSD 5.4

SPONSORED LINKS