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.
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.
POSIX.1-2001, POSIX.1-2008, C89, C99. In C89,
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 5.10 of the Linux
project. A description of the project, information about reporting bugs,
and the latest version of this page, can be found at