ttyname, ttyname_r - return name of a terminal
char *ttyname(int desc);
int ttyname_r(int desc, char *buf, size_t buflen);
ttyname() returns a pointer to the NUL-terminated pathname of the terminal
device that is open on the file descriptor desc, or NULL on error (for
example, if desc is not connected to a terminal). The return value may point
to static data, possibly overwritten by the next call. The function ttyname_r()
stores this pathname in the buffer buf of length buflen.
function ttyname() returns a pointer to a pathname on success. On error,
NULL is returned, and errno is set appropriately. The function ttyname_r()
returns 0 on success, and an error number upon error.
in errno by a failing ttyname() or returned by a failing ttyname_r():
- Bad file descriptor.
- File descriptor does not refer to a terminal
- buflen was too small to allow storing the pathname.