Manual Pages  — DEVNAME

devname – get device name

LIBRARY SYNOPSIS DESCRIPTION EXAMPLES SEE ALSO HISTORY

Standard C Library (libc, -lc)

#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);

The devname() 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.

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));

The devname() function appeared in BSD 4.4 . The fdevname() function appeared in FreeBSD 8.0 .