NetBSD/lib/libc/gen/getdevmajor.3
2004-12-16 17:29:55 +00:00

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.\" $NetBSD: getdevmajor.3,v 1.3 2004/12/16 17:29:55 wiz Exp $
.\"
.\" Copyright (c) 2004 The NetBSD Foundation, Inc.
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.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Andrew Brown.
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.Dd December 15, 2004
.Dt GETDEVMAJOR 3
.Os
.Sh NAME
.Nm getdevmajor
.Nd get block or character device major number
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In stdlib.h
.In sys/stat.h
.Ft dev_t
.Fn getdevmajor "const char *name" "mode_t type"
.Sh DESCRIPTION
The
.Fn getdevmajor
function returns the major device number of the block or character
device specified by
.Ar name
and a file type matching the one encoded in
.Fa type
which must be one of
.Dv S_IFBLK
or
.Dv S_IFCHR .
.Sh RETURN VALUES
If no device matches the specified values, no information is
available, or an error occurs,
.Dv (dev_t)~0
is returned and
.Va errno
is set to indicate the error.
.Sh EXAMPLES
To retrieve the major number for
.Xr pty 4
slave devices (aka pts devices):
.Bd -literal -offset indent
#include \*[Lt]stdlib.h\*[Gt]
#include \*[Lt]sys/stat.h\*[Gt]
.sp
dev_t pts;
pts = getdevmajor("pts", S_IFCHR);
.Ed
.Pp
To retrieve the major numbers for the block and character
.Xr wd 4
devices:
.Bd -literal -offset indent
#include \*[Lt]stdlib.h\*[Gt]
#include \*[Lt]sys/stat.h\*[Gt]
.sp
dev_t c, b;
c = getdevmajor("wd", S_IFCHR);
b = getdevmajor("wd", S_IFBLK);
.Ed
.Sh ERRORS
The
.Fn getdevmajor
function may fail and set
.Va errno
for any of the errors specified for the library functions
.Xr malloc 3
and
.Xr sysctlbyname 3 .
In addition, the following errors may be reported:
.Bl -tag -width Er
.It Bq Er EINVAL
The value of the
.Fa major
argument is not
.Dv S_IFCHR
or
.Dv S_IFBLK .
.It Bq Er ENOENT
The named device is not found.
.El
.Sh SEE ALSO
.Xr stat 2 ,
.Xr devname 3 ,
.Xr malloc 3 ,
.Xr sysctlbyname 3
.Sh HISTORY
The
.Fn getdevmajor
function call appeared in
.Nx 3.0 .