98 lines
3.3 KiB
Groff
98 lines
3.3 KiB
Groff
.\" Copyright (c) 1985, 1991, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
.\" must display the following acknowledgement:
|
|
.\" This product includes software developed by the University of
|
|
.\" California, Berkeley and its contributors.
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)sigreturn.2 8.1 (Berkeley) 6/4/93
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd June 4, 1993
|
|
.Dt SIGRETURN 2
|
|
.Os
|
|
.Sh NAME
|
|
.Nm sigreturn
|
|
.Nd return from signal
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In signal.h
|
|
.Ft int
|
|
.Fn sigreturn "ucontext_t *scp"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn sigreturn
|
|
system call
|
|
allows users to atomically unmask, switch stacks,
|
|
and return from a signal context.
|
|
The processes signal mask and stack status are
|
|
restored from the context structure pointed to by
|
|
.Fa scp .
|
|
The system call does not return;
|
|
the users stack pointer, frame pointer, argument pointer,
|
|
and processor status longword are restored from the context.
|
|
Execution resumes at the specified pc.
|
|
This system call is used by the trampoline code and
|
|
.Xr longjmp 3
|
|
when returning from a signal to the previously executing program.
|
|
.Sh NOTES
|
|
This system call is not available in
|
|
.Bx 4.2
|
|
hence it should not be used if backward compatibility is needed.
|
|
.Sh RETURN VALUES
|
|
If successful, the system call does not return.
|
|
Otherwise, a value of -1 is returned and
|
|
.Va errno
|
|
is set to indicate the error.
|
|
.Sh ERRORS
|
|
The
|
|
.Fn sigreturn
|
|
system call
|
|
will fail and the process context will remain unchanged
|
|
if one of the following occurs.
|
|
.Bl -tag -width Er
|
|
.It Bq Er EFAULT
|
|
The
|
|
.Fa scp
|
|
argument
|
|
points to memory that is not a valid part of the process
|
|
address space.
|
|
.It Bq Er EINVAL
|
|
The process status longword is invalid or would improperly
|
|
raise the privilege level of the process.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr sigvec 2 ,
|
|
.Xr setjmp 3 ,
|
|
.Xr ucontext 3
|
|
.Sh HISTORY
|
|
The
|
|
.Fn sigreturn
|
|
system call appeared in
|
|
.Bx 4.3 .
|