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.