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	1	.\" Copyright (c) 1990, 1991, 1993
	2	.\" The Regents of the University of California. All rights reserved.
	3	.\"
	4	.\" This code is derived from software contributed to Berkeley by
	5	.\" the American National Standards Committee X3, on Information
	6	.\" Processing Systems.
	7	.\"
	8	.\" Redistribution and use in source and binary forms, with or without
	9	.\" modification, are permitted provided that the following conditions
	10	.\" are met:
	11	.\" 1. Redistributions of source code must retain the above copyright
	12	.\" notice, this list of conditions and the following disclaimer.
	13	.\" 2. Redistributions in binary form must reproduce the above copyright
	14	.\" notice, this list of conditions and the following disclaimer in the
	15	.\" documentation and/or other materials provided with the distribution.
	16	.\" 3. All advertising materials mentioning features or use of this software
	17	.\" must display the following acknowledgement:
	18	.\" This product includes software developed by the University of
	19	.\" California, Berkeley and its contributors.
	20	.\" 4. Neither the name of the University nor the names of its contributors
	21	.\" may be used to endorse or promote products derived from this software
	22	.\" without specific prior written permission.
	23	.\"
	24	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	25	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	26	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	27	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	28	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	29	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	30	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	31	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	32	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	33	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	34	.\" SUCH DAMAGE.
	35	.\"
	36	.\" @(#)setjmp.3 8.1 (Berkeley) 6/4/93
	37	.\" $FreeBSD: src/lib/libc/gen/setjmp.3,v 1.9 2001/10/01 16:08:51 ru Exp $
	38	.\"
	39	.Dd June 4, 1993
	40	.Dt SETJMP 3
	41	.Os
	42	.Sh NAME
	43	.Nm sigsetjmp ,
	44	.Nm siglongjmp ,
	45	.Nm setjmp ,
	46	.Nm longjmp ,
	47	.Nm _setjmp ,
	48	.Nm _longjmp ,
	49	.Nm longjmperror
	50	.Nd non-local jumps
	51	.Sh LIBRARY
	52	.Lb libc
	53	.Sh SYNOPSIS
	54	.In setjmp.h
	55	.Ft int
	56	.Fn sigsetjmp "sigjmp_buf env" "int savemask"
	57	.Ft void
	58	.Fn siglongjmp "sigjmp_buf env" "int val"
	59	.Ft int
	60	.Fn setjmp "jmp_buf env"
	61	.Ft void
	62	.Fn longjmp "jmp_buf env" "int val"
	63	.Ft int
	64	.Fn _setjmp "jmp_buf env"
	65	.Ft void
	66	.Fn _longjmp "jmp_buf env" "int val"
	67	.Ft void
	68	.Fn longjmperror void
	69	.Sh DESCRIPTION
	70	The
	71	.Fn sigsetjmp ,
	72	.Fn setjmp ,
	73	and
	74	.Fn _setjmp
	75	functions save their calling environment in
	76	.Fa env .
	77	Each of these functions returns 0.
	78	.Pp
	79	The corresponding
	80	.Fn longjmp
	81	functions restore the environment saved by their most recent respective
	82	invocations
	83	of the
	84	.Fn setjmp
	85	function.
	86	They then return so that program execution continues as if the corresponding
	87	invocation of the
	88	.Fn setjmp
	89	call had just returned the value specified by
	90	.Fa val ,
	91	instead of 0.
	92	.Pp
	93	Pairs of calls may be intermixed, i.e. both
	94	.Fn sigsetjmp
	95	and
	96	.Fn siglongjmp
	97	and
	98	.Fn setjmp
	99	and
	100	.Fn longjmp
	101	combinations may be used in the same program, however, individual
	102	calls may not, e.g. the
	103	.Fa env
	104	argument to
	105	.Fn setjmp
	106	may not be passed to
	107	.Fn siglongjmp .
	108	.Pp
	109	The
	110	.Fn longjmp
	111	routines may not be called after the routine which called the
	112	.Fn setjmp
	113	routines returns.
	114	.Pp
	115	All accessible objects have values as of the time
	116	.Fn longjmp
	117	routine was called, except that the values of objects of automatic storage
	118	invocation duration that do not have the
	119	.Em volatile
	120	type and have been changed between the
	121	.Fn setjmp
	122	invocation and
	123	.Fn longjmp
	124	call are indeterminate.
	125	.Pp
	126	The
	127	.Fn setjmp Ns / Ns Fn longjmp
	128	pairs save and restore the signal mask while
	129	.Fn _setjmp Ns / Ns Fn _longjmp
	130	pairs save and restore only the register set and the stack.
	131	(See
	132	.Fn sigprocmask 2 . )
	133	.Pp
	134	The
	135	.Fn sigsetjmp Ns / Ns Fn siglongjmp
	136	function
	137	pairs save and restore the signal mask if the argument
	138	.Fa savemask
	139	is non-zero, otherwise only the register set and the stack are saved.
	140	.Sh ERRORS
	141	If the contents of the
	142	.Fa env
	143	are corrupted, or correspond to an environment that has already returned,
	144	the
	145	.Fn longjmp
	146	routine calls the routine
	147	.Fn longjmperror 3 .
	148	If
	149	.Fn longjmperror
	150	returns the program is aborted (see
	151	.Xr abort 3 ) .
	152	The default version of
	153	.Fn longjmperror
	154	prints the message
	155	.Dq Li longjmp botch
	156	to standard error and returns.
	157	User programs wishing to exit more gracefully should write their own
	158	versions of
	159	.Fn longjmperror .
	160	.Sh SEE ALSO
	161	.Xr sigaction 2 ,
	162	.Xr sigaltstack 2 ,
	163	.Xr signal 3
	164	.Sh STANDARDS
	165	The
	166	.Fn setjmp
	167	and
	168	.Fn longjmp
	169	functions conform to
	170	.St -isoC .
	171	The
	172	.Fn sigsetjmp
	173	and
	174	.Fn siglongjmp
	175	functions conform to
	176	.St -p1003.1-88 .