_longjmp(3p) — Linux manual page

_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(3p) and setjmp(3p).

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 termination. If the
       function has returned, the results are undefined.

       Passing longjmp() a pointer to a buffer not created by setjmp(),
       passing _longjmp() a pointer to a buffer not created by
       _setjmp(), passing siglongjmp() a pointer to a buffer not created
       by sigsetjmp(), or passing 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 removed in a future
       version.

SEE ALSO

       longjmp(3p), setjmp(3p), siglongjmp(3p), sigsetjmp(3p)

       The Base Definitions volume of POSIX.1‐2017, setjmp.h(0p)

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 .

IEEE/The Open Group               2017                      _LONGJMP(3P)

Pages that refer to this page: setjmp.h(0p), sigaction(3p)

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