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.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved 

.TH "SIGSETJMP" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"

.\" sigsetjmp 

.SH NAME

sigsetjmp \- set jump point for a non-local goto

.SH SYNOPSIS

.LP

\fB#include <setjmp.h>

.br

.sp

int sigsetjmp(sigjmp_buf\fP \fIenv\fP\fB, int\fP \fIsavemask\fP\fB);

\fP

\fB

.br

\fP

.SH DESCRIPTION

.LP

The \fIsigsetjmp\fP() function shall be equivalent to the \fIsetjmp\fP()

function,

except as follows:

.IP " *" 3

References to \fIsetjmp\fP() are equivalent to \fIsigsetjmp\fP().

.LP

.IP " *" 3

References to \fIlongjmp\fP() are equivalent to \fIsiglongjmp\fP().

.LP

.IP " *" 3

If the value of the \fIsavemask\fP argument is not 0, \fIsigsetjmp\fP()

shall also save the current signal mask of the calling

thread as part of the calling environment.

.LP

.SH RETURN VALUE

.LP

If the return is from a successful direct invocation, \fIsigsetjmp\fP()

shall return 0. If the return is from a call to \fIsiglongjmp\fP(),

\fIsigsetjmp\fP() shall return a non-zero value.

.SH ERRORS

.LP

No errors are defined.

.LP

\fIThe following sections are informative.\fP

.SH EXAMPLES

.LP

None.

.SH APPLICATION USAGE

.LP

The distinction between \fIsetjmp\fP()/ \fIlongjmp\fP() and \fIsigsetjmp\fP()/

\fIsiglongjmp\fP() is only significant for programs which use \fIsigaction\fP(),

\fIsigprocmask\fP(), or \fIsigsuspend\fP().

.LP

Note that since this function is defined in terms of \fIsetjmp\fP(),

if \fIsavemask\fP

is zero, it is unspecified whether the signal mask is saved.

.SH RATIONALE

.LP

The ISO\ C standard specifies various restrictions on the usage of

the \fIsetjmp\fP() 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\fP() macro.

.LP

There are processors that cannot easily support these calls, but this

was not considered a sufficient reason to exclude

them.

.LP

4.2 BSD, 4.3 BSD, and XSI-conformant systems provide functions named

\fI_setjmp\fP()

and \fI_longjmp\fP() that, together with \fIsetjmp\fP() and \fIlongjmp\fP(),

provide the same

functionality as \fIsigsetjmp\fP() and \fIsiglongjmp\fP(). On those

systems, \fIsetjmp\fP() and \fIlongjmp\fP() save and restore signal

masks, while \fI_setjmp\fP() and \fI_longjmp\fP() do not. On System

V Release 3 and in corresponding issues of the SVID, \fIsetjmp\fP()

and \fIlongjmp\fP() are explicitly defined

not to save and restore signal masks. In order to permit existing

practice in both cases, the relation of \fIsetjmp\fP() and \fIlongjmp\fP()

to signal masks is not

specified, and a new set of functions is defined instead.

.LP

The \fIlongjmp\fP() and \fIsiglongjmp\fP()

functions operate as in the previous issue provided the matching \fIsetjmp\fP()

or

\fIsigsetjmp\fP() 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

.LP

None.

.SH SEE ALSO

.LP

\fIsiglongjmp\fP() , \fIsignal\fP() , \fIsigprocmask\fP() , \fIsigsuspend\fP()

, the Base Definitions volume of

IEEE\ Std\ 1003.1-2001, \fI<setjmp.h>\fP

.SH 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 .