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

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
       _longjmp, _setjmp - non-local goto
SYNOPSIS
       #include <setjmp.h>
       void _longjmp(jmp_buf env, int val);
       int _setjmp(jmp_buf env);

DESCRIPTION
       The _longjmp() and _setjmp() functions shall be equivalent to longjmp()
       and  setjmp(),  respectively,  with  the  additional  restriction  that
       _longjmp() and _setjmp() shall not manipulate the signal mask.
       If _longjmp() is called even though env was never initialized by a call
       to  _setjmp(),  or  when  the last such call was in a function that has
       since returned, the results are undefined.
RETURN VALUE
       Refer to longjmp() and setjmp().
ERRORS
       No errors are defined.
       The following sections are informative.
EXAMPLES
       None.
APPLICATION USAGE
       If _longjmp() is executed and the environment in  which  _setjmp()  was
       executed  no  longer  exists,  errors  can occur.  The conditions under
       which the environment of the _setjmp() no longer exists include exiting
       the  function  that  contains  the _setjmp() call, and exiting an inner
       block with temporary storage.  This condition might not be  detectable,
       in  which  case the _longjmp() occurs and, if the environment no longer
       exists, the contents of the temporary storage of  an  inner  block  are
       unpredictable.  This condition might also cause unexpected process ter-
       mination. If the function has returned, the results are undefined.
       Passing longjmp() a pointer to a buffer not created by setjmp(),  pass-
       ing  _longjmp() a pointer to a buffer not created by _setjmp(), passing
       siglongjmp() a pointer to a buffer not created by sigsetjmp(), or pass-
       ing any of these three functions a buffer that has been modified by the
       user can cause all the problems listed above, and more.
       The _longjmp() and _setjmp() functions are included to support programs
       written  to  historical system interfaces.  New applications should use
       siglongjmp() and sigsetjmp() respectively.
RATIONALE
       None.
FUTURE DIRECTIONS
       The _longjmp() and _setjmp() functions may be marked LEGACY in a future
       version.
SEE ALSO
       longjmp(),  setjmp(),  siglongjmp(),  sigsetjmp(), the Base Definitions
       volume of IEEE Std 1003.1-2001, <setjmp.h>
COPYRIGHT
       Portions of this text are reprinted and reproduced in  electronic  form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
       -- 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 http://www.opengroup.org/unix/online.html .

IEEE/The Open Group                  2003                         _LONGJMP(3P)