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Clarify interpretation of 'addr'; plus a few other minor edits and updates.

This commit is contained in:
Michael Kerrisk 2007-12-25 17:06:46 +00:00
parent 781b97e6a4
commit 498c6aa666
1 changed files with 20 additions and 13 deletions
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33
man2/arch_prctl.2
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@ -21,24 +21,33 @@
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.TH ARCH_PRCTL 2 2003-02-02 "Linux" "Linux Programmer's Manual"
.TH ARCH_PRCTL 2 2007-12-26 "Linux" "Linux Programmer's Manual"
.SH NAME
arch_prctl \- set architecture specific thread state
arch_prctl \- set architecture-specific thread state
.SH SYNOPSIS
.nf
.B #include <asm/prctl.h>
.br
.B #include <sys/prctl.h>
.sp
.BI "int arch_prctl(int " code ", unsigned long " addr );
.BI "int arch_prctl(int " code ", unsigned long *" addr );
.fi
.SH DESCRIPTION
The
.BR arch_prctl ()
function sets architecture specific process or thread state.
function sets architecture-specific process or thread state.
.I code
selects a subfunction
and passes argument
.I addr
to it.
to it;
.I addr
is interpreted as either an
.I "unsigned long"
for the "set" operations, or as an
.IR "unsigned long *" ,
for the "get" operations.
.LP
Sub functions for x86-64 are:
.TP
@ -53,9 +62,8 @@ Return the 64-bit base value for the
.I FS
register of the current thread in the
.I unsigned long
pointed to by the
.I address
parameter.
pointed to
.IR addr .
.TP
.B ARCH_SET_GS
Set the 64-bit base for the
@ -68,11 +76,10 @@ Return the 64-bit base value for the
.I GS
register of the current thread in the
.I unsigned long
pointed to by the
.I address
parameter.
pointed to
.IR addr .
.SH RETURN VALUE
On sucess,
On success,
.BR arch_prctl ()
returns 0; on error, \-1 is returned, and
.I errno
@ -111,7 +118,7 @@ segment selector by setting up an LDT with
.BR modify_ldt (2)
or using the
.BR set_thread_area (2)
system call in a 2.5 kernel.
system call in kernel 2.5 or later.
.BR arch_prctl ()
is only needed when you want to set bases that are larger than 4GB.
Memory in the first 2GB of address space can be allocated by using
@ -120,7 +127,7 @@ with the
.B MAP_32BIT
flag.
As of version 2.3.5, glibc provides no prototype for
As of version 2.7, glibc provides no prototype for
.BR arch_prctl ().
You have to declare it yourself for now.
This may be fixed in future glibc versions.