PROLOG

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of
       this interface may differ (consult the corresponding 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 functionality described on this reference page is aligned with the ISO C standard. Any
       conflict between the requirements described here and the ISO C standard is  unintentional.
       This volume of POSIX.1‐2017 defers to the ISO C standard.

       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

       None.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       abort(), stdin

       The Base Definitions volume of POSIX.1‐2017, <assert.h>

COPYRIGHT

       Portions  of  this  text  are  reprinted  and  reproduced in electronic form from IEEE Std
       1003.1-2017, Standard for Information Technology -- Portable  Operating  System  Interface
       (POSIX),  The  Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 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 http://www.opengroup.org/unix/online.html .

       Any  typographical  or  formatting errors that appear in this page are most likely to have
       been introduced during the conversion of the source files to man page  format.  To  report
       such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .