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assert(3) [opendarwin man page]

ASSERT(3)						     Linux Programmer's Manual							 ASSERT(3)

assert - abort the program if assertion is false SYNOPSIS
#include <assert.h> void assert(scalar expression); DESCRIPTION
This macro can help programmers find bugs in their programs, or handle exceptional cases via a crash that will produce limited debugging output. If 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-deterministi- cally. 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 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 4.15 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
2017-09-15 ASSERT(3)

Check Out this Related Man Page

ASSERT(3P)						     POSIX Programmer's Manual							ASSERT(3P)

This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond- ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux. NAME
assert - insert program diagnostics SYNOPSIS
#include <assert.h> void assert(scalar expression); DESCRIPTION
The assert() macro shall insert diagnostics into programs; it shall expand to a void expression. When it is executed, if expression (which shall have a scalar type) is false (that is, compares equal to 0), assert() shall write information about the particular call that failed on stderr and shall call abort(). The information written about the call that failed shall include the text of the argument, the name of the source file, the source file line number, and the name of the enclosing function; the latter are, respectively, the values of the preprocessing macros __FILE__ and __LINE__ and of the identifier __func__. Forcing a definition of the name NDEBUG, either from the compiler command line or with the preprocessor control statement #define NDEBUG ahead of the #include <assert.h> statement, shall stop assertions from being compiled into the program. RETURN VALUE
The assert() macro shall not return a value. ERRORS
No errors are defined. The following sections are informative. EXAMPLES
abort(), stderr, the Base Definitions volume of IEEE Std 1003.1-2001, <assert.h> COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol- ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at . IEEE
/The Open Group 2003 ASSERT(3P)
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