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
behaviour 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)
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