diff options
Diffstat (limited to 'lib/libc/gen/siginterrupt.3')
| -rw-r--r-- | lib/libc/gen/siginterrupt.3 | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/lib/libc/gen/siginterrupt.3 b/lib/libc/gen/siginterrupt.3 new file mode 100644 index 000000000000..e790132b3703 --- /dev/null +++ b/lib/libc/gen/siginterrupt.3 @@ -0,0 +1,119 @@ +.\" 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. +.\" 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. +.\" +.\" @(#)siginterrupt.3 8.1 (Berkeley) 6/4/93 +.\" $FreeBSD$ +.\" +.Dd June 4, 1993 +.Dt SIGINTERRUPT 3 +.Os +.Sh NAME +.Nm siginterrupt +.Nd allow signals to interrupt system calls +.Sh LIBRARY +.Lb libc +.Sh SYNOPSIS +.In signal.h +.Ft int +.Fn siginterrupt "int sig" "int flag" +.Sh DESCRIPTION +The +.Fn siginterrupt +function +is used to change the system call restart +behavior when a system call is interrupted by the specified signal. +If the flag is false (0), then system calls will be restarted if +they are interrupted by the specified signal +and no data has been transferred yet. +System call restart has been the default behavior since +.Bx 4.2 , +and is the default behaviour for +.Xr signal 3 +on +.Fx . +.Pp +If the flag is true (1), +then restarting of system calls is disabled. +If a system call is interrupted by the specified signal +and no data has been transferred, +the system call will return \-1 with the global variable +.Va errno +set to +.Er EINTR . +Interrupted system calls that have started transferring +data will return the amount of data actually transferred. +System call interrupt is the signal behavior found on +.Bx 4.1 +and +.At V +systems. +.Pp +Note that the new +.Bx 4.2 +signal handling semantics are not +altered in any other way. +Most notably, signal handlers always remain installed until +explicitly changed by a subsequent +.Xr sigaction 2 +call, and the signal mask operates as documented in +.Xr sigaction 2 . +Programs may switch between restartable and interruptible +system call operation as often as desired in the execution of a program. +.Pp +Issuing a +.Fn siginterrupt 3 +call during the execution of a signal handler will cause +the new action to take place on the next signal to be caught. +.Sh NOTES +This library routine uses an extension of the +.Xr sigaction 2 +system call that is not available in +.Bx 4.2 , +hence it should not be used if backward compatibility is needed. +.Sh RETURN VALUES +.Rv -std siginterrupt +.Sh ERRORS +The +.Fn siginterrupt +call fails if: +.Bl -tag -width Er +.It Bq Er EINVAL +The +.Fa sig +argument +is not a valid signal number. +.El +.Sh SEE ALSO +.Xr sigaction 2 , +.Xr sigprocmask 2 , +.Xr sigsuspend 2 , +.Xr signal 3 +.Sh HISTORY +The +.Fn siginterrupt +function appeared in +.Bx 4.3 . |