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.
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.
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.
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.
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) 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.unix.org/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
IEEE/The Open Group 2013 SIGSETJMP(3P)