NetBSD/lib/libc/gen/getdevmajor.3

.\"	$NetBSD: getdevmajor.3,v 1.2 2004/12/16 04:07:22 christos Exp $
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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 S_IFBLK or 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 errno is set to indicate the error.
.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 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 SEE ALSO
.Xr stat 2 ,
.Xr devname 3 ,
.Xr malloc 3 ,
.Xr sysctlbyname 3 .
.Sh HISTORY
The
.Nm getdevmajor
function call appeared in
.Nx 3.0 .