assert(3) [netbsd man page]

ASSERT(3)						   BSD Library Functions Manual 						 ASSERT(3)

NAME

     assert -- expression verification macro

SYNOPSIS

     #include <assert.h>

     assert(expression);

DESCRIPTION

     The assert() macro tests the given expression and if it is false, the calling process is terminated.  A diagnostic message, consisting of the
     text of the expression, the name of the source file, the line number and the enclosing function, is written to stderr and the abort(3) func-
     tion is called, effectively terminating the program.

     If expression is true, the assert() macro does nothing.

     The assert() macro may be removed at compile time with the cc(1) option -DNDEBUG.

DIAGNOSTICS

     The following diagnostic message is written to stderr if expression is false:

	   "assertion "%s" failed: file "%s", line %d, function "%s"
", 
			       "expression", __FILE__, __LINE__, __func__);

SEE ALSO

     cc(1), _DIAGASSERT(3), abort(3)

STANDARDS

     The assert() macro conforms to ISO/IEC 9899:1999 (``ISO C99'').

HISTORY

     A assert macro appeared in Version 6 AT&T UNIX.

     Information on the name of the enclosing function appeared in ISO/IEC 9899:1999 (``ISO C99'').

BSD
								 January 22, 2007							       BSD

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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 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.

RETURN VALUE

       No value is returned.

CONFORMING TO

       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.

BUGS

       assert() is implemented as a macro; if the expression tested has side-effects, program behavior will be different depending on whether NDE-
       BUG 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 3.27 of the Linux man-pages project.  A description of the project, and information about reporting bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.

GNU
								    2002-08-25								 ASSERT(3)

Linux and UNIX Man Pages

assert(3) [netbsd man page]

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