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

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GNU                                                2015-08-08                                          ASSERT(3)