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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ATTRIBUTES | CONFORMING TO | BUGS | SEE ALSO | COLOPHON |
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ASSERT(3) Linux Programmer's Manual ASSERT(3)
assert - abort the program if assertion is false
#include <assert.h>
void assert(scalar expression);
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-deterministically.
No value is returned.
For an explanation of the terms used in this section, see
attributes(7).
┌──────────┬───────────────┬─────────┐
│Interface │ Attribute │ Value │
├──────────┼───────────────┼─────────┤
│assert() │ Thread safety │ MT-Safe │
└──────────┴───────────────┴─────────┘
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.
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.
abort(3), assert_perror(3), exit(3)
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)
Pages that refer to this page: abort(3), assert_perror(3)
Copyright and license for this manual page
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