'\" et
.TH SIGSETJMP "3P" 2013 "IEEE/The Open Group" "POSIX Programmer's Manual"
.SH 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.

.SH NAME
sigsetjmp
\(em set jump point for a non-local goto
.SH SYNOPSIS
.LP
.nf
#include <setjmp.h>
.P
int sigsetjmp(sigjmp_buf \fIenv\fP, int \fIsavemask\fP);
.fi
.SH DESCRIPTION
The
\fIsigsetjmp\fR()
function shall be equivalent to the
\fIsetjmp\fR()
function, except as follows:
.IP " *" 4
References to
\fIsetjmp\fR()
are equivalent to
\fIsigsetjmp\fR().
.IP " *" 4
References to
\fIlongjmp\fR()
are equivalent to
\fIsiglongjmp\fR().
.IP " *" 4
If the value of the
.IR savemask
argument is not 0,
\fIsigsetjmp\fR()
shall also save the current signal mask of the calling thread as part
of the calling environment.
.SH "RETURN VALUE"
If the return is from a successful direct invocation,
\fIsigsetjmp\fR()
shall return 0. If the return is from a call to
\fIsiglongjmp\fR(),
\fIsigsetjmp\fR()
shall return a non-zero value.
.SH ERRORS
No errors are defined.
.LP
.IR "The following sections are informative."
.SH EXAMPLES
None.
.SH "APPLICATION USAGE"
The distinction between
\fIsetjmp\fR()/\c
\fIlongjmp\fR()
and
\fIsigsetjmp\fR()/\c
\fIsiglongjmp\fR()
is only significant for programs which use
\fIsigaction\fR(),
\fIsigprocmask\fR(),
or
\fIsigsuspend\fR().
.P
Note that since this function is defined in terms of
\fIsetjmp\fR(),
if
.IR savemask
is zero, it is unspecified whether the signal mask is saved.
.SH RATIONALE
The ISO\ C standard specifies various restrictions on the usage of the
\fIsetjmp\fR()
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
\fIsigsetjmp\fR()
macro.
.P
There are processors that cannot easily support these calls, but this
was not considered a sufficient reason to exclude them.
.P
4.2 BSD, 4.3 BSD, and XSI-conformant systems provide functions named
\fI_setjmp\fR()
and
\fI_longjmp\fR()
that, together with
\fIsetjmp\fR()
and
\fIlongjmp\fR(),
provide the same functionality as
\fIsigsetjmp\fR()
and
\fIsiglongjmp\fR().
On those systems,
\fIsetjmp\fR()
and
\fIlongjmp\fR()
save and restore signal masks, while
\fI_setjmp\fR()
and
\fI_longjmp\fR()
do not. On System V Release 3
and in corresponding issues of the SVID,
\fIsetjmp\fR()
and
\fIlongjmp\fR()
are explicitly defined not to save and restore signal masks. In order
to permit existing practice in both cases, the relation of
\fIsetjmp\fR()
and
\fIlongjmp\fR()
to signal masks is not specified, and a new set of functions is defined
instead.
.P
The
\fIlongjmp\fR()
and
\fIsiglongjmp\fR()
functions operate as in the previous issue provided the matching
\fIsetjmp\fR()
or
\fIsigsetjmp\fR()
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.
.SH "FUTURE DIRECTIONS"
None.
.SH "SEE ALSO"
.IR "\fIpthread_sigmask\fR\^(\|)",
.IR "\fIsiglongjmp\fR\^(\|)",
.IR "\fIsignal\fR\^(\|)",
.IR "\fIsigsuspend\fR\^(\|)"
.P
The Base Definitions volume of POSIX.1\(hy2008,
.IR "\fB<setjmp.h>\fP"
.SH COPYRIGHT
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 .

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