mirror of https://github.com/mkerrisk/man-pages
101 lines
3.6 KiB
Plaintext
101 lines
3.6 KiB
Plaintext
.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
|
|
.TH "LONGJMP" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
|
|
.\" longjmp
|
|
.SH NAME
|
|
longjmp \- non-local goto
|
|
.SH SYNOPSIS
|
|
.LP
|
|
\fB#include <setjmp.h>
|
|
.br
|
|
.sp
|
|
void longjmp(jmp_buf\fP \fIenv\fP\fB, int\fP \fIval\fP\fB);
|
|
.br
|
|
\fP
|
|
.SH DESCRIPTION
|
|
.LP
|
|
The \fIlongjmp\fP() function shall restore the environment saved by
|
|
the most recent invocation of \fIsetjmp\fP() in the same thread, with
|
|
the corresponding \fBjmp_buf\fP argument. If there is no
|
|
such invocation, or if the function containing the invocation of \fIsetjmp\fP()
|
|
has
|
|
terminated execution in the interim, or if the invocation of \fIsetjmp\fP()
|
|
was within the
|
|
scope of an identifier with variably modified type and execution has
|
|
left that scope in the interim, the behavior is undefined.
|
|
\ It is unspecified whether \fIlongjmp\fP() restores the signal mask,
|
|
leaves the signal mask unchanged, or restores it to its
|
|
value at the time \fIsetjmp\fP() was called.
|
|
.LP
|
|
All accessible objects have values, and all other components of the
|
|
abstract machine have state (for example, floating-point
|
|
status flags and open files), as of the time \fIlongjmp\fP() was called,
|
|
except that the values of objects of automatic storage
|
|
duration are unspecified if they meet all the following conditions:
|
|
.IP " *" 3
|
|
They are local to the function containing the corresponding \fIsetjmp\fP()
|
|
invocation.
|
|
.LP
|
|
.IP " *" 3
|
|
They do not have volatile-qualified type.
|
|
.LP
|
|
.IP " *" 3
|
|
They are changed between the \fIsetjmp\fP() invocation and \fIlongjmp\fP()
|
|
call.
|
|
.LP
|
|
.LP
|
|
As
|
|
it bypasses the usual function call and return mechanisms, \fIlongjmp\fP()
|
|
shall execute correctly in contexts of interrupts,
|
|
signals, and any of their associated functions. However, if \fIlongjmp\fP()
|
|
is invoked from a nested signal handler (that is, from
|
|
a function invoked as a result of a signal raised during the handling
|
|
of another signal), the behavior is undefined.
|
|
.LP
|
|
The effect of a call to \fIlongjmp\fP() where initialization of the
|
|
\fBjmp_buf\fP structure was not performed in the calling
|
|
thread is undefined.
|
|
.SH RETURN VALUE
|
|
.LP
|
|
After \fIlongjmp\fP() is completed, program execution continues as
|
|
if the corresponding invocation of \fIsetjmp\fP() had just returned
|
|
the value specified by \fIval\fP. The \fIlongjmp\fP() function
|
|
shall not cause \fIsetjmp\fP() to return 0; if \fIval\fP is 0, \fIsetjmp\fP()
|
|
shall return 1.
|
|
.SH ERRORS
|
|
.LP
|
|
No errors are defined.
|
|
.LP
|
|
\fIThe following sections are informative.\fP
|
|
.SH EXAMPLES
|
|
.LP
|
|
None.
|
|
.SH APPLICATION USAGE
|
|
.LP
|
|
Applications whose behavior depends on the value of the signal mask
|
|
should not use \fIlongjmp\fP() and \fIsetjmp\fP(), since their effect
|
|
on the signal mask is unspecified, but should instead use the \fIsiglongjmp\fP()
|
|
and \fIsigsetjmp\fP()
|
|
functions (which can save and restore the signal mask under application
|
|
control).
|
|
.SH RATIONALE
|
|
.LP
|
|
None.
|
|
.SH FUTURE DIRECTIONS
|
|
.LP
|
|
None.
|
|
.SH SEE ALSO
|
|
.LP
|
|
\fIsetjmp\fP() , \fIsigaction\fP() , \fIsiglongjmp\fP() , \fIsigsetjmp\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 .
|