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

       siglongjmp()  ,  signal()  ,  sigprocmask()  ,  sigsuspend()   ,   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 .