ASSERT - reference manual online

Abort the program if assertion is false.

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 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 programmers find bugs in their programs. 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.
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 NDEBUG 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 4.04 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
GNU 2015-08-08 ASSERT(3)
This manual Reference Other manuals
assert(3) referred by assert_perror(3) | mdb_internal(3)
refer to abort(3) | assert_perror(3) | attributes(7) | exit(3)