redhat man page for assert

ASSERT(3)						     Linux Programmer's Manual							 ASSERT(3)

NAME
       assert - abort the program if assertion is false

SYNOPSIS
       #include <assert.h>

       void assert(scalar expression);

DESCRIPTION
       If the macro NDEBUG was defined at the moment <assert.h> was last included, the macro assert() generates no code, and hence does nothing at
       all.  Otherwise, the macro assert() prints an error message to standard output and terminates the program by calling abort() if	expression
       is false (i.e., compares equal to zero).

       The  purpose  of  this  macro  is  to  help  the programmer find bugs in his program. The message "assertion failed in file foo.c, function
       do_bar(), line 1287" is of no help at all to a user.

RETURN VALUE
       No value is returned.

CONFORMING TO
       ISO9899 (ANSI C).  In the 1990 standard, expression is required to be of type int and undefined behavior results if it is not, but  in  the
       1999 standard it may have any scalar type.

BUGS
       assert()  is  implemented  as  a macro; if the expression tested has side-effects, program behaviour will be different depending on whether
       NDEBUG is defined.  This may create Heisenbugs which go away when debugging is turned on.

SEE ALSO
       exit(3), abort(3), assert_perror(3)

C99								    2002-08-25								 ASSERT(3)