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assert(3)                BSD Library Functions Manual                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 abort(3) function is called, effectively terminating the program.

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

     The assert() macro may be removed at compile time with the cc(1) option
     -DNDEBUG.


DIAGNOSTICS

     The following diagnostic message is written to stderr if expression is
     false:

           "assertion \"%s\" failed: file \"%s\", line %d\n", \
                               "expression", __FILE__, __LINE__);


SEE ALSO

     cc(1), abort(3)


STANDARDS

     The assert() macro conforms to ANSI X3.159-1989 (``ANSI C89'').


HISTORY

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

BSD                              June 9, 1993                              BSD

Mac OS X 10.8 - Generated Sun Aug 26 12:24:45 CDT 2012