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. 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.Dd April 2, 2022 33.Dt SETJMP 3 34.Os 35.Sh NAME 36.Nm sigsetjmp , 37.Nm siglongjmp , 38.Nm setjmp , 39.Nm longjmp , 40.Nm _setjmp , 41.Nm _longjmp , 42.Nm longjmperror 43.Nd non-local jumps 44.Sh LIBRARY 45.Lb libc 46.Sh SYNOPSIS 47.In setjmp.h 48.Ft int 49.Fn sigsetjmp "sigjmp_buf env" "int savemask" 50.Ft void 51.Fn siglongjmp "sigjmp_buf env" "int val" 52.Ft int 53.Fn setjmp "jmp_buf env" 54.Ft void 55.Fn longjmp "jmp_buf env" "int val" 56.Ft int 57.Fn _setjmp "jmp_buf env" 58.Ft void 59.Fn _longjmp "jmp_buf env" "int val" 60.Ft void 61.Fn longjmperror void 62.Sh DESCRIPTION 63The 64.Fn sigsetjmp , 65.Fn setjmp , 66and 67.Fn _setjmp 68functions save their calling environment in 69.Fa env . 70Each of these functions returns 0. 71.Pp 72The corresponding 73.Fn longjmp 74functions restore the environment saved by their most recent respective 75invocations 76of the 77.Fn setjmp 78function. 79They then return so that program execution continues as if the corresponding 80invocation of the 81.Fn setjmp 82call had just returned the value specified by 83.Fa val , 84instead of 0. 85.Pp 86Pairs of calls may be intermixed, i.e., both 87.Fn sigsetjmp 88and 89.Fn siglongjmp 90and 91.Fn setjmp 92and 93.Fn longjmp 94combinations may be used in the same program, however, individual 95calls may not, e.g.\& the 96.Fa env 97argument to 98.Fn setjmp 99may not be passed to 100.Fn siglongjmp . 101.Pp 102The 103.Fn longjmp 104routines may not be called after the routine which called the 105.Fn setjmp 106routines returns. 107.Pp 108All accessible objects have values as of the time 109.Fn longjmp 110routine was called, except that the values of objects of automatic storage 111invocation duration that do not have the 112.Vt volatile 113type and have been changed between the 114.Fn setjmp 115invocation and 116.Fn longjmp 117call are indeterminate. 118.Pp 119The 120.Fn setjmp Ns / Ns Fn longjmp 121pairs save and restore the signal mask while 122.Fn _setjmp Ns / Ns Fn _longjmp 123pairs save and restore only the register set and the stack. 124(See 125.Fn sigprocmask 2 . ) 126.Pp 127The 128.Fn sigsetjmp Ns / Ns Fn siglongjmp 129function 130pairs save and restore the signal mask if the argument 131.Fa savemask 132is non-zero, otherwise only the register set and the stack are saved. 133.Sh ERRORS 134If the contents of the 135.Fa env 136are corrupted, or correspond to an environment that has already returned, 137the 138.Fn longjmp 139routine calls the routine 140.Fn longjmperror 3 . 141If 142.Fn longjmperror 143returns the program is aborted (see 144.Xr abort 3 ) . 145The default version of 146.Fn longjmperror 147prints the message 148.Dq Li longjmp botch 149to standard error and returns. 150User programs wishing to exit more gracefully should write their own 151versions of 152.Fn longjmperror . 153.Sh SEE ALSO 154.Xr sigaction 2 , 155.Xr sigaltstack 2 , 156.Xr signal 3 157.Sh STANDARDS 158The 159.Fn setjmp 160and 161.Fn longjmp 162functions conform to 163.St -isoC . 164The 165.Fn sigsetjmp 166and 167.Fn siglongjmp 168functions conform to 169.St -p1003.1-88 . 170.Sh HISTORY 171The 172.Fn setjmp 173and 174.Fn longjmp 175functions first appeared in the Programmer's Workbench (PWB/UNIX). 176