sigsetjmp(3p) [centos man 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 correspond-
       ing 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(),  sigproc-
       mask(), 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 Technol-
       ogy -- 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 .

IEEE
/The Open Group						       2003							     SIGSETJMP(3P)