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 .