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

       This  macro  can  help programmers find bugs in their programs, or handle exceptional cases via a crash that will produce limited debugging
       output.

       If expression is false (i.e., compares equal to zero), assert() prints an error message to standard error and  terminates  the  program	by
       calling	abort(3).   The error message includes the name of the file and function containing the assert() call, the source code line number
       of the call, and the text of the argument; something like:

	   prog: some_file.c:16: some_func: Assertion `val == 0' failed.

       If the macro NDEBUG is defined at the moment <assert.h> was last included, the macro assert() generates no code, and hence does nothing	at
       all.   It  is not recommended to define NDEBUG if using assert() to detect error conditions since the software may behave non-deterministi-
       cally.

RETURN VALUE

       No value is returned.

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       +----------+---------------+---------+
       |Interface | Attribute	  | Value   |
       +----------+---------------+---------+
       |assert()  | Thread safety | MT-Safe |
       +----------+---------------+---------+

CONFORMING TO

       POSIX.1-2001, POSIX.1-2008, C89, C99.  In C89, expression is required to be of type int and undefined behavior results if it is not, but in
       C99 it may have any scalar type.

BUGS

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

SEE ALSO

       abort(3), assert_perror(3), exit(3)

COLOPHON

       This page is part of release 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and  the
       latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

GNU
								    2017-09-15								 ASSERT(3)