mirror of https://github.com/mkerrisk/man-pages
101 lines
2.8 KiB
Groff
101 lines
2.8 KiB
Groff
.\" Written by Michael Haardt, Fri Nov 25 14:51:42 MET 1994
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.\"
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.\" This is free documentation; you can redistribute it and/or
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.\" modify it under the terms of the GNU General Public License as
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.\" published by the Free Software Foundation; either version 2 of
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.\" the License, or (at your option) any later version.
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.\"
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.\" The GNU General Public License's references to "object code"
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.\" and "executables" are to be interpreted as the output of any
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.\" document formatting or typesetting system, including
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.\" intermediate and printed output.
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.\"
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.\" This manual is distributed in the hope that it will be useful,
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.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
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.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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.\" GNU General Public License for more details.
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.\"
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.\" You should have received a copy of the GNU General Public
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.\" License along with this manual; if not, write to the Free
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.\" Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111,
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.\" USA.
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.\"
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.\" Added sigsetjmp, Sun Mar 2 22:03:05 EST 1997, jrv@vanzandt.mv.com
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.\" Modifications, Sun Feb 26 14:39:45 1995, faith@cs.unc.edu
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.\" "
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.TH SETJMP 3 2008-08-29 "" "Linux Programmer's Manual"
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.SH NAME
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setjmp, sigsetjmp \- save stack context for non-local goto
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.SH SYNOPSIS
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.B #include <setjmp.h>
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.sp
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.nf
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.BI "int setjmp(jmp_buf " env );
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.BI "int sigsetjmp(sigjmp_buf " env ", int " savesigs );
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.fi
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.sp
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.in -4n
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Feature Test Macro Requirements for glibc (see
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.BR feature_test_macros (7)):
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.in
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.sp
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.BR sigsetjmp ():
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_POSIX_C_SOURCE\ >=\ 1 || _XOPEN_SOURCE || _POSIX_C_SOURCE
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.SH DESCRIPTION
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.BR setjmp ()
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and
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.BR longjmp (3)
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are useful for dealing with errors
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and interrupts encountered in a low-level subroutine of a program.
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.BR setjmp ()
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saves the stack context/environment in \fIenv\fP for
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later use by
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.BR longjmp (3).
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The stack context will be invalidated
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if the function which called
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.BR setjmp ()
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returns.
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.P
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.BR sigsetjmp ()
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is similar to
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.BR setjmp ().
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If \fIsavesigs\fP is non-zero,
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the set of blocked signals is saved in \fIenv\fP and will be restored
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if a
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.BR siglongjmp (3)
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is later performed with this \fIenv\fP.
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.SH "RETURN VALUE"
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.BR setjmp ()
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and
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.BR sigsetjmp ()
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return 0 if returning directly, and
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non-zero when returning from
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.BR longjmp (3)
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using the saved context.
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.SH "CONFORMING TO"
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C89, C99, and POSIX.1-2001 specify
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.BR setjmp ().
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POSIX.1-2001 specifies
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.BR sigsetjmp ().
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.SH NOTES
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POSIX does not specify whether
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.BR setjmp ()
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will save the
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signal context.
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(In System V it will not.
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In 4.3BSD it will, and there
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is a function \fB_setjmp\fP that will not.)
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If you want to save signal masks, use
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.BR sigsetjmp ().
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.P
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.BR setjmp ()
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and
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.BR sigsetjmp ()
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make programs hard to understand
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and maintain.
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If possible an alternative should be used.
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.SH "SEE ALSO"
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.BR longjmp (3),
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.BR siglongjmp (3)
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