1.\" $NetBSD: ucontext.2,v 1.1 2003/10/14 14:59:04 wiz Exp $ 2.\" 3.\" Copyright (c) 2001 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Klaus Klein. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 3. All advertising materials mentioning features or use of this software 18.\" must display the following acknowledgement: 19.\" This product includes software developed by the NetBSD 20.\" Foundation, Inc. and its contributors. 21.\" 4. Neither the name of The NetBSD Foundation nor the names of its 22.\" contributors may be used to endorse or promote products derived 23.\" from this software without specific prior written permission. 24.\" 25.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 26.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 29.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35.\" POSSIBILITY OF SUCH DAMAGE. 36.\" 37.Dd June 13, 2001 38.Dt UCONTEXT 2 39.Os 40.Sh NAME 41.Nm ucontext 42.Nd user context 43.Sh SYNOPSIS 44.In ucontext.h 45.Sh DESCRIPTION 46.Nm ucontext_t 47is a structure type which is used to describe the context of a 48thread of control within the execution of a process. 49.Pp 50.Nm ucontext_t 51includes the following members: 52.Bd -literal -offset indent 53ucontext_t * uc_link 54sigset_t uc_sigmask 55stack_t uc_stack 56mcontext_t uc_mcontext 57.Ed 58.Pp 59The 60.Fa uc_link 61member points to the context that will be resumed after the function 62specified when modifying a context using 63.Xr makecontext 3 64has returned. 65If 66.Fa uc_link 67is a null pointer, then the context is the main context, 68and the process will exit with an exit status of 0 upon return. 69.Pp 70The 71.Fa uc_sigmask 72member is the set of signals that are blocked when the context is 73activated. 74Further information can be found in 75.Xr sigprocmask 2 . 76.Pp 77The 78.Fa uc_stack 79member defines the stack used by the context. 80Further information can be found in 81.Xr sigaltstack 2 . 82.Pp 83The 84.Fa uc_mcontext 85member defines the machine state associated with the context; 86it may consist of general registers, floating point registers 87and other machine-specific infomation. 88Its description is beyond the scope of this manual page; 89portable applications should not access this structure member. 90.Sh SEE ALSO 91.Xr _exit 2 , 92.Xr getcontext 2 , 93.Xr setcontext 2 , 94.Xr sigaltstack 2 , 95.Xr sigprocmask 2 , 96.Xr makecontext 3 , 97.Xr swapcontext 3 98.Sh STANDARDS 99The 100.Nm ucontext_t 101type conforms to 102.St -xsh5 . 103.Sh HISTORY 104The 105.Fn makecontext 106and 107.Fn swapcontext 108functions first appeared in 109.At V.4 . 110