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