Module Name: src
Committed By: dsl
Date: Fri Aug 7 19:34:46 UTC 2009
Modified Files:
src/lib/libc/sys: syscall.2
Log Message:
Add text to the description saying that normal applications should not
use syscall().
Add text to bugs saying that high bits of the syscall number may be masked.
Fixes bug PR/11088
To generate a diff of this commit:
cvs rdiff -u -r1.17 -r1.18 src/lib/libc/sys/syscall.2
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/lib/libc/sys/syscall.2
diff -u src/lib/libc/sys/syscall.2:1.17 src/lib/libc/sys/syscall.2:1.18
--- src/lib/libc/sys/syscall.2:1.17 Fri Nov 23 20:29:40 2007
+++ src/lib/libc/sys/syscall.2 Fri Aug 7 19:34:46 2009
@@ -1,4 +1,4 @@
-.\" $NetBSD: syscall.2,v 1.17 2007/11/23 20:29:40 dsl Exp $
+.\" $NetBSD: syscall.2,v 1.18 2009/08/07 19:34:46 dsl Exp $
.\"
.\" Copyright (c) 1980, 1991, 1993
.\" The Regents of the University of California. All rights reserved.
@@ -29,7 +29,7 @@
.\"
.\" @(#)syscall.2 8.1 (Berkeley) 6/16/93
.\"
-.Dd November 23, 2006
+.Dd August 7, 2009
.Dt SYSCALL 2
.Os
.Sh NAME
@@ -57,8 +57,10 @@
.Nm __syscall
form should be used when one or more of the parameters is a
64-bit argument to ensure that argument alignment is correct.
+.Pp
This system call is useful for testing new system calls that
do not have entries in the C library.
+It should not be used in normal applications.
.Sh RETURN VALUES
The return values are defined by the system call being invoked.
In general, a 0 return value indicates success.
@@ -83,6 +85,9 @@
(with %o0 containing the most significant part) so a 32 bit right shift
of the result is needed to get a correct 32 bit result.
.Pp
+Many architectures mask off the unwanted high bits of the syscall number,
+rather than returning an error.
+.Pp
Due to ABI implementation differences in passing struct or union
type arguments to system calls between different processors, all
system calls pass instead pointers to such structs or unions, even
