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assert — abort the program if assertion is false
#include <assert.h>
void
assert( |
scalar expression); |
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 error and terminates the program by calling
abort(3) 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.
POSIX.1-2001, 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.
assert() is implemented as a
macro; if the expression tested has side-effects, program
behavior will be different depending on whether NDEBUG is defined. This may create
Heisenbugs which go away when debugging is turned on.
This page is part of release 3.52 of the Linux man-pages project. A
description of the project, and information about reporting
bugs, can be found at
http://www.kernel.org/doc/man−pages/.
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Copyright (c) 1993 by Thomas Koenig (ig25rz.uni-karlsruhe.de) %%%LICENSE_START(VERBATIM) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. %%%LICENSE_END Modified Sat Jul 24 21:42:42 1993 by Rik Faith <faithcs.unc.edu> Modified Tue Oct 22 23:44:11 1996 by Eric S. Raymond <esrthyrsus.com> |