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.\" $FreeBSD$ 38.\" 39.Dd June 4, 1993 40.Dt SETJMP 3 41.Os BSD 4 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 SYNOPSIS 52.Fd #include <setjmp.h> 53.Ft int 54.Fn sigsetjmp "sigjmp_buf env" "int savemask" 55.Ft void 56.Fn siglongjmp "sigjmp_buf env" "int val" 57.Ft int 58.Fn setjmp "jmp_buf env" 59.Ft void 60.Fn longjmp "jmp_buf env" "int val" 61.Ft int 62.Fn _setjmp "jmp_buf env" 63.Ft void 64.Fn _longjmp "jmp_buf env" "int val" 65.Ft void 66.Fn longjmperror void 67.Sh DESCRIPTION 68The 69.Fn sigsetjmp , 70.Fn setjmp , 71and 72.Fn _setjmp 73functions save their calling environment in 74.Fa env . 75Each of these functions returns 0. 76.Pp 77The corresponding 78.Fn longjmp 79functions restore the environment saved by their most recent respective 80invocations 81of the 82.Fn setjmp 83function. 84They then return so that program execution continues as if the corresponding 85invocation of the 86.Fn setjmp 87call had just returned the value specified by 88.Fa val , 89instead of 0. 90.Pp 91Pairs of calls may be intermixed, i.e. both 92.Fn sigsetjmp 93and 94.Fn siglongjmp 95and 96.Fn setjmp 97and 98.Fn longjmp 99combinations may be used in the same program, however, individual 100calls may not, e.g. the 101.Fa env 102argument to 103.Fn setjmp 104may not be passed to 105.Fn siglongjmp . 106.Pp 107The 108.Fn longjmp 109routines may not be called after the routine which called the 110.Fn setjmp 111routines returns. 112.Pp 113All accessible objects have values as of the time 114.Fn longjmp 115routine was called, except that the values of objects of automatic storage 116invocation duration that do not have the 117.Em volatile 118type and have been changed between the 119.Fn setjmp 120invocation and 121.Fn longjmp 122call are indeterminate. 123.Pp 124The 125.Fn setjmp Ns / Ns Fn longjmp 126pairs save and restore the signal mask while 127.Fn _setjmp Ns / Ns Fn _longjmp 128pairs save and restore only the register set and the stack. 129(See 130.Fn sigprocmask 2 . ) 131.Pp 132The 133.Fn sigsetjmp Ns / Ns Fn siglongjmp 134function 135pairs save and restore the signal mask if the argument 136.Fa savemask 137is non-zero, otherwise only the register set and the stack are saved. 138.Sh ERRORS 139If the contents of the 140.Fa env 141are corrupted, or correspond to an environment that has already returned, 142the 143.Fn longjmp 144routine calls the routine 145.Fn longjmperror 3 . 146If 147.Fn longjmperror 148returns the program is aborted (see 149.Xr abort 3 ) . 150The default version of 151.Fn longjmperror 152prints the message 153.Dq Li longjmp botch 154to standard error and returns. 155User programs wishing to exit more gracefully should write their own 156versions of 157.Fn longjmperror . 158.Sh SEE ALSO 159.Xr sigaction 2 , 160.Xr sigaltstack 2 , 161.Xr signal 3 162.Sh STANDARDS 163The 164.Fn setjmp 165and 166.Fn longjmp 167functions conform to 168.St -ansiC . 169The 170.Fn sigsetjmp 171and 172.Fn siglongjmp 173functions conform to 174.St -p1003.1-88 . 175