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author | archie <archie@FreeBSD.org> | 2002-09-11 21:39:21 +0000 |
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committer | archie <archie@FreeBSD.org> | 2002-09-11 21:39:21 +0000 |
commit | b2c4f4ae74d752a0bcd8d9b06e316c98bd3c4f6e (patch) | |
tree | c0a1a2ecda59cdda3c24fde5dd815ca40b5ad45f /lib/libc/gen/getcontext.3 | |
parent | f185fabd5ba1e9fd15f860872f46027c04833340 (diff) | |
download | FreeBSD-src-b2c4f4ae74d752a0bcd8d9b06e316c98bd3c4f6e.zip FreeBSD-src-b2c4f4ae74d752a0bcd8d9b06e316c98bd3c4f6e.tar.gz |
Add man pages for getcontext()/setcontext(), makecontext()/swapcontext(),
and ucontext_t.
Reviewed by: mini
MFC after: 3 days
Diffstat (limited to 'lib/libc/gen/getcontext.3')
-rw-r--r-- | lib/libc/gen/getcontext.3 | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/lib/libc/gen/getcontext.3 b/lib/libc/gen/getcontext.3 new file mode 100644 index 0000000..de1e4a4 --- /dev/null +++ b/lib/libc/gen/getcontext.3 @@ -0,0 +1,119 @@ +.\" Copyright (c) 2002 Packet Design, LLC. +.\" All rights reserved. +.\" +.\" Subject to the following obligations and disclaimer of warranty, +.\" use and redistribution of this software, in source or object code +.\" forms, with or without modifications are expressly permitted by +.\" Packet Design; provided, however, that: +.\" +.\" (i) Any and all reproductions of the source or object code +.\" must include the copyright notice above and the following +.\" disclaimer of warranties; and +.\" (ii) No rights are granted, in any manner or form, to use +.\" Packet Design trademarks, including the mark "PACKET DESIGN" +.\" on advertising, endorsements, or otherwise except as such +.\" appears in the above copyright notice or in the software. +.\" +.\" THIS SOFTWARE IS BEING PROVIDED BY PACKET DESIGN "AS IS", AND +.\" TO THE MAXIMUM EXTENT PERMITTED BY LAW, PACKET DESIGN MAKES NO +.\" REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING +.\" THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED +.\" WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, +.\" OR NON-INFRINGEMENT. PACKET DESIGN DOES NOT WARRANT, GUARANTEE, +.\" OR MAKE ANY REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS +.\" OF THE USE OF THIS SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, +.\" RELIABILITY OR OTHERWISE. IN NO EVENT SHALL PACKET DESIGN BE +.\" LIABLE FOR ANY DAMAGES RESULTING FROM OR ARISING OUT OF ANY USE +.\" OF THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY DIRECT, +.\" INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, PUNITIVE, OR CONSEQUENTIAL +.\" DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, LOSS OF +.\" USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER 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 PACKET DESIGN IS ADVISED OF +.\" THE POSSIBILITY OF SUCH DAMAGE. +.\" +.\" $FreeBSD$ +.\" +.Dd Sep 10, 2002 +.Dt GETCONTEXT 3 +.Os +.Sh NAME +.Nm getcontext +.Nm setcontext +.Nd get and set user thread context +.Sh LIBRARY +.Lb libc +.Sh SYNOPSIS +.In ucontext.h +.Ft int +.Fn getcontext "ucontext_t *ucp" +.Ft int +.Fn setcontext "const ucontext_t *ucp" +.Sh DESCRIPTION +.Fn getcontext +saves the current thread's execution context in the structure pointed to by +.Fa "ucp" . +This saved context may then later be restored by calling +.Fn setcontext . +.Pp +.Fn setcontext +makes a previously saved thread context the current thread context, i.e., +the current context is lost and +.Fn setcontext +does not return. +Instead, execution continues in the context specified by +.Fa "ucp" , +which must have been previously initialized by a call to +.Fn setcontext , +.Fn makecontext , +or by being passed as an argument to a signal handler (see +.Xr sigaction 2) . +.Pp +If +.Fa ucp +was initialized by +.Fn getcontext , +then execution continues as if the original +.Fn getcontext +call had just returned (again). +.Pp +If +.Fa ucp +was initialized by +.Fn makecontext , +execution continues with the invocation of the function specified to +.Fn makecontext . +When that function returns, +.Fa "ucp->uc_link" +determines what happens next: +if +.Fa "ucp->uc_link" +is +.Dv NULL , +the process exits; +otherwise, +.Fn setcontext "ucp->uc_link" +is implicitly invoked. +.Pp +If +.Fa ucp +was initialized by the invocation of a signal handler, execution continues +at the point the thread was interrupted by the signal. +.Ed +.Sh RETURN VALUES +If successful, +.Fn getcontext +returns zero and +.Fn setcontext +does not return; otherwise -1 is returned. +.Sh ERRORS +No errors are defined for +.Fn getcontext +or +.Fn setcontext . +.Sh SEE ALSO +.Xr sigaction 2 , +.Xr sigaltstack 2 , +.Xr makecontext 3 , +.Xr ucontext 3 |