167 lines
4.6 KiB
Groff
167 lines
4.6 KiB
Groff
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.\" Copyright (c) 1990, 1991 The Regents of the University of California.
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.\" All rights reserved.
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.\"
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.\" This code is derived from software contributed to Berkeley by
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.\" the American National Standards Committee X3, on Information
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.\" Processing Systems.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)setjmp.3 6.8 (Berkeley) 7/30/91
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.\"
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.Dd July 30, 1991
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.Dt SETJMP 3
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.Os BSD 4
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.Sh NAME
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.Nm sigsetjmp ,
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.Nm siglongjmp ,
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.Nm setjmp ,
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.Nm longjmp ,
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.Nm _setjmp ,
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.Nm _longjmp longjmperror
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.Nd non-local jumps
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.Sh SYNOPSIS
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.Fd #include <setjmp.h>
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.Ft int
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.Fn sigsetjmp "sigjmp_buf env" "int savemask"
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.Ft void
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.Fn siglongjmp "sigjmp_buf env" "int val"
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.Ft int
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.Fn setjmp "jmp_buf env"
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.Ft void
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.Fn longjmp "jmp_buf env" "int val"
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.Ft int
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.Fn _setjmp "jmp_buf env"
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.Ft void
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.Fn _longjmp "jmp_buf env" "int val"
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.Ft void
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.Fn longjmperror void
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.Sh DESCRIPTION
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The
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.Fn sigsetjmp ,
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.Fn setjmp ,
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and
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.Fn _setjmp
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functions save their calling environment in
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.Fa env .
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Each of these functions returns 0.
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.Pp
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The corresponding
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.Fn longjmp
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functions restore the environment saved by their most recent respective
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invocations
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of the
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.Fn setjmp
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function.
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They then return so that program execution continues as if the corresponding
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invocation of the
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.Fn setjmp
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call had just returned the value specified by
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.Fa val ,
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instead of 0.
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.Pp
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Pairs of calls may be intermixed, i.e. both
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.Fn sigsetjmp
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and
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.Fn siglongjmp
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and
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.Fn setjmp
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and
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.Fn longjmp
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combinations may be used in the same program, however, individual
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calls may not, i.e. the
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.Fa env
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argument to
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.Fn sigsetjmp
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may not be passed to
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.Fn longjmp .
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.Pp
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The
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.Fn longjmp
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routines may not be called after the routine which called the
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.Fn setjmp
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routines returns.
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.Pp
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All accessible objects have values as of the time
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.Fn longjmp
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routine was called, except that the values of objects of automatic storage
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invocation duration that do not have the
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.Em volatile
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type and have been changed between the
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.Fn setjmp
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invocation and
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.Fn longjmp
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call are indeterminate.
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.Pp
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The
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.Fn setjmp Ns / Ns Fn longjmp
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pairs save and restore the signal mask while
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.Fn _setjmp Ns / Ns Fn _longjmp
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pairs save and restore only the register set and the stack.
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(See
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.Fn sigmask 2 . )
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.Pp
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The
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.Fn sigsetjmp Ns / Ns Fn siglongjmp
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function
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pairs save and restore the signal mask if the argument
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.Fa savemask
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is non-zero, otherwise only the register set and the stack are saved.
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.Sh ERRORS
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If the contents of the
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.Fa env
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are corrupted, or correspond to an environment that has already returned,
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the
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.Fn longjmp
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routine calls the routine
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.Fn longjmperror 3 .
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If
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.Fn longjmperror
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returns the program is aborted (see
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.Xr abort 2 ) .
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The default version of
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.Fn longjmperror
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prints the message
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.Dq Li longjmp botch
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to standard error and returns.
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User programs wishing to exit more gracefully should write their own
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versions of
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.Fn longjmperror .
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.Sh SEE ALSO
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.Xr sigaction 2 ,
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.Xr sigstack 2 ,
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.Xr signal 3
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.Sh STANDARDS
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The
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.Fn setjmp
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and
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.Fn longjmp
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functions conform to
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.St -ansiC .
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