124 lines
3.6 KiB
Groff
124 lines
3.6 KiB
Groff
.\" Copyright (c) 2002 Packet Design, LLC.
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.\" All rights reserved.
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.\"
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.\" Subject to the following obligations and disclaimer of warranty,
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.\" use and redistribution of this software, in source or object code
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.\" forms, with or without modifications are expressly permitted by
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.\" Packet Design; provided, however, that:
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.\"
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.\" (i) Any and all reproductions of the source or object code
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.\" must include the copyright notice above and the following
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.\" disclaimer of warranties; and
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.\" (ii) No rights are granted, in any manner or form, to use
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.\" Packet Design trademarks, including the mark "PACKET DESIGN"
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.\" on advertising, endorsements, or otherwise except as such
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.\" appears in the above copyright notice or in the software.
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.\"
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.\" THIS SOFTWARE IS BEING PROVIDED BY PACKET DESIGN "AS IS", AND
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.\" TO THE MAXIMUM EXTENT PERMITTED BY LAW, PACKET DESIGN MAKES NO
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.\" REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING
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.\" THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED
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.\" WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE,
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.\" OR NON-INFRINGEMENT. PACKET DESIGN DOES NOT WARRANT, GUARANTEE,
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.\" OR MAKE ANY REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS
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.\" OF THE USE OF THIS SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY,
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.\" RELIABILITY OR OTHERWISE. IN NO EVENT SHALL PACKET DESIGN BE
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.\" LIABLE FOR ANY DAMAGES RESULTING FROM OR ARISING OUT OF ANY USE
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.\" OF THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY DIRECT,
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.\" INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, PUNITIVE, OR CONSEQUENTIAL
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.\" DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, LOSS OF
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.\" USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY THEORY OF
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.\" LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
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.\" THE USE OF THIS SOFTWARE, EVEN IF PACKET DESIGN IS ADVISED OF
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.\" THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd March 23, 2020
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.Dt UCONTEXT 3
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.Os
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.Sh NAME
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.Nm ucontext
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.Nd user thread context
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In ucontext.h
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.Sh DESCRIPTION
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The
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.Vt ucontext_t
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type is a structure type suitable for holding the context for a user
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thread of execution.
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A thread's context includes its stack, saved registers, and list of
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blocked signals.
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.Pp
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The
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.Vt ucontext_t
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structure contains at least these fields:
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.Pp
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.Bl -tag -width ".Va mcontext_t\ \ uc_mcontext" -offset 3n -compact
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.It Va "ucontext_t *uc_link"
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context to assume when this one returns
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.It Va "sigset_t uc_sigmask"
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signals being blocked
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.It Va "stack_t uc_stack"
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stack area
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.It Va "mcontext_t uc_mcontext"
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saved registers
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.El
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.Pp
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The
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.Va uc_link
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field points to the context to resume when this context's entry point
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function returns.
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If
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.Va uc_link
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is equal to
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.Dv NULL ,
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then the process exits when this context returns.
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.Pp
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The
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.Va uc_mcontext
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field is machine-dependent and should be treated as opaque by
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portable applications.
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.Pp
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The following functions are defined to manipulate
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.Vt ucontext_t
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structures:
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.Pp
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.Bl -item -offset 3n -compact
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.It
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.Ft int
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.Fn getcontext "ucontext_t *" ;
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.It
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.Ft "ucontext_t *"
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.Fn getcontextx "void" ;
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.It
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.Ft int
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.Fn setcontext "const ucontext_t *" ;
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.It
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.Ft void
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.Fn makecontext "ucontext_t *" "void \*[lp]*\*[rp]\*[lp]void\*[rp]" int ... ;
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.It
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.Ft int
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.Fn swapcontext "ucontext_t *" "const ucontext_t *" ;
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.El
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.Sh SEE ALSO
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.Xr sigaltstack 2 ,
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.Xr getcontext 3 ,
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.Xr getcontextx 3 ,
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.Xr makecontext 3
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.Sh STANDARDS
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The
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.Vt ucontext_t
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type conforms to
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.St -xsh5
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and
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.St -p1003.1-2001 .
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The
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.St -p1003.1-2008
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revision removed the
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.Vt ucontext_t
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from the specification.
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