minix/lib/libc/sys/_lwp_getprivate.2

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.\" $NetBSD: _lwp_getprivate.2,v 1.6 2013/10/05 09:18:56 njoly Exp $
.\"
.\" Copyright (c) 2003 The NetBSD Foundation, Inc.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Jason R. Thorpe of Wasabi Systems, Inc.
.\"
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.\" modification, are permitted provided that the following conditions
.\" are met:
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.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.Dd September 7, 2013
.Dt _LWP_GETPRIVATE 2
.Os
.Sh NAME
.Nm _lwp_getprivate ,
.Nm _lwp_setprivate
.Nd get and set light-weight process private data
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In lwp.h
.Ft void *
.Fn _lwp_getprivate void
.Ft void
.Fn _lwp_setprivate "void *ptr"
.Sh DESCRIPTION
.Fn _lwp_setprivate
stores the pointer to private data
.Fa ptr
in a location private to the LWP.
.Pp
.Fn _lwp_getprivate
returns the pointer to private data for the LWP.
.Pp
Some platforms provide alternative ways quicker than
.Fn _lwp_getprivate
to use the pointer.
.Bl -tag -width amd64
.It alpha
The pointer can be retrieved by call_pal PAL_rdunique.
.It amd64
The base address of
.Dv %fs
register is set to the pointer so that the private data can be
accessed using the selector.
.It i386
The base address of
.Dv %gs
register is set to the pointer so that the private data can be
accessed using the selector.
.It sparc
.Dv %g7
register is set to the pointer.
.El
.Sh ERRORS
The
.Fn _lwp_getprivate
and
.Fn _lwp_setprivate
functions are always successful, and no return value is reserved to indicate
an error.
.Sh SEE ALSO
.Xr _lwp_makecontext 3
.Sh HISTORY
The
.Fn _lwp_getprivate
and
.Fn _lwp_setprivate
system calls first appeared in
.Nx 2.0 .