diff options
| author |   otto <otto@openbsd.org> | 2005-04-16 18:19:59 +0000 |
|---|---|---|
| committer | otto <otto@openbsd.org> | 2005-04-16 18:19:59 +0000 |
| commit | 6da20159bca654a5dfab5f5a3443b32e74623837 (patch) | |
| tree | f98570c1c9fc8be59981699f9b65565b02cf6e64 /lib/libc | |
| parent | Since the return value from the *_info functions is only actually used as a (diff) | |
| download | wireguard-openbsd-6da20159bca654a5dfab5f5a3443b32e74623837.tar.xz wireguard-openbsd-6da20159bca654a5dfab5f5a3443b32e74623837.zip | |
Describe __syscall(2) in all its ugliness. ok jmc@ tom@ millert@
deraadt@
Diffstat (limited to 'lib/libc')
| -rw-r--r-- | lib/libc/sys/syscall.2 | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/lib/libc/sys/syscall.2 b/lib/libc/sys/syscall.2 index cb720c205a0..f357b45f67e 100644 --- a/lib/libc/sys/syscall.2 +++ b/lib/libc/sys/syscall.2 @@ -1,4 +1,4 @@ -.\" $OpenBSD: syscall.2,v 1.7 2003/06/02 20:18:39 millert Exp $ +.\" $OpenBSD: syscall.2,v 1.8 2005/04/16 18:19:59 otto Exp $ .\" $NetBSD: syscall.2,v 1.4 1995/02/27 12:38:53 cgd Exp $ .\" .\" Copyright (c) 1980, 1991, 1993 @@ -42,7 +42,6 @@ .Fd #include <unistd.h> .Ft int .Fn syscall "int number" "..." -.Ft int .Fn __syscall "quad_t number" "..." .Sh DESCRIPTION .Fn syscall @@ -52,6 +51,14 @@ interface has the specified with the specified arguments. Symbolic constants for system calls can be found in the header file .Ao Pa sys/syscall.h Ac . +.Pp +Since different system calls have different return types, a +prototype of +.Nm __syscall +specifying the correct return type should be declared locally. +This is especially important for system calls returning +larger-than-int results. +.Pp The .Nm __syscall form should be used when one or more of the parameters is a @@ -60,7 +67,9 @@ This system call is useful for testing new system calls that do not have entries in the C library. .Sh RETURN VALUES The return values are defined by the system call being invoked. -In general, a 0 return value indicates success. +In general, for system calls returning +.Va int , +a 0 return value indicates success. A \-1 return value indicates an error, and an error code is stored in .Va errno . |