sigsetjmp(3p) — Linux manual page

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

       sigsetjmp — set jump point for a non-local goto

SYNOPSIS

       #include <setjmp.h>

       int sigsetjmp(sigjmp_buf env, int savemask);

DESCRIPTION

       The sigsetjmp() function shall be equivalent to the setjmp()
       function, except as follows:

        *  References to setjmp() are equivalent to sigsetjmp().

        *  References to longjmp() are equivalent to siglongjmp().

        *  If the value of the savemask argument is not 0, sigsetjmp()
           shall also save the current signal mask of the calling thread
           as part of the calling environment.

RETURN VALUE

       If the return is from a successful direct invocation, sigsetjmp()
       shall return 0. If the return is from a call to siglongjmp(),
       sigsetjmp() shall return a non-zero value.

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       The distinction between setjmp()/longjmp() and
       sigsetjmp()/siglongjmp() is only significant for programs which
       use sigaction(), sigprocmask(), or sigsuspend().

       Note that since this function is defined in terms of setjmp(), if
       savemask is zero, it is unspecified whether the signal mask is
       saved.

RATIONALE

       The ISO C standard specifies various restrictions on the usage of
       the setjmp() macro in order to permit implementors to recognize
       the name in the compiler and not implement an actual function.
       These same restrictions apply to the sigsetjmp() macro.

       There are processors that cannot easily support these calls, but
       this was not considered a sufficient reason to exclude them.

       4.2 BSD, 4.3 BSD, and XSI-conformant systems provide functions
       named _setjmp() and _longjmp() that, together with setjmp() and
       longjmp(), provide the same functionality as sigsetjmp() and
       siglongjmp().  On those systems, setjmp() and longjmp() save and
       restore signal masks, while _setjmp() and _longjmp() do not. On
       System V Release 3 and in corresponding issues of the SVID,
       setjmp() and longjmp() are explicitly defined not to save and
       restore signal masks. In order to permit existing practice in
       both cases, the relation of setjmp() and longjmp() to signal
       masks is not specified, and a new set of functions is defined
       instead.

       The longjmp() and siglongjmp() functions operate as in the
       previous issue provided the matching setjmp() or sigsetjmp() has
       been performed in the same thread. Non-local jumps into contexts
       saved by other threads would be at best a questionable practice
       and were not considered worthy of standardization.

FUTURE DIRECTIONS

       None.

SEE ALSO

       pthread_sigmask(3p), siglongjmp(3p), signal(3p), sigsuspend(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                     SIGSETJMP(3P)

Pages that refer to this page: setjmp.h(0p), longjmp(3p), _longjmp(3p), setjmp(3p), sigaltstack(3p), siglongjmp(3p), sleep(3p)

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