NAME
devname —
get device name
LIBRARY
library “libc”
SYNOPSIS
#include
<sys/stat.h>
#include <stdlib.h>
char *
devname(dev_t
dev, mode_t
type);
char *
devname_r(dev_t
dev, mode_t type,
char *buf,
int len);
char *
fdevname(int
fd);
char *
fdevname_r(int
fd, char *buf,
int len);
DESCRIPTION
Thedevname()
function returns a pointer to the name of the block or character device in
/dev with a device number of
dev, and a file type matching the one encoded in
type which must be one of
S_IFBLK or S_IFCHR. To find
the right name, devname() asks the kernel via the
kern.devname sysctl. If it is unable to come up with a
suitable name, it will format the information encapsulated in
dev and type in a human-readable
format.
The
fdevname()
and
fdevname_r()
function obtains the device name directly from a file descriptor pointing to
a character device. If it is unable to come up with a suitable name, these
functions will return a NULL pointer.
devname()
and fdevname() return the name stored in a static
buffer which will be overwritten on subsequent calls.
devname_r()
and fdevname_r() take a buffer and length as
argument to avoid this problem.
EXAMPLES
int fd;
struct stat buf;
char *name;
fd = open("/dev/tun");
fstat(fd, &buf);
printf("devname is /dev/%s\n", devname(buf.st_rdev, S_IFCHR));
printf("fdevname is /dev/%s\n", fdevname(fd));
SEE ALSO
HISTORY
The devname() function appeared in
4.4BSD. The fdevname()
function appeared in FreeBSD 8.0.