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(), siglongjmp(), signal(), sigsuspend()

       The Base Definitions volume of POSIX.1‐2017, <setjmp.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 .

IEEE/The Open Group                                   2017                                     SIGSETJMP(3POSIX)