dirfd − get directory stream file descriptor

#include <sys/types.h>
#include <dirent.h>

int dirfd(DIR *dir);

The function dirfd() returns the file descriptor associated with the directory stream dir.

This descriptor is the one used internally by the directory stream. As a result, it is only useful for functions which do not depend on or alter the file position, such as fstat(2) and fchdir(2). It will be automatically closed when closedir(3) is called.

On error −1 is returned.

The prototype for dirfd is only available if _BSD_SOURCE or _SVID_SOURCE is defined (either explicitly, or implicitly, by not defining _POSIX_SOURCE or compiling with the -ansi flag).

This is a BSD extension, present in 4.3BSD-Reno, not in 4.2BSD. Present in libc5 (since 5.1.2) and in glibc2.

open(2), closedir(3), opendir(3), readdir(3), rewinddir(3), scandir(3), seekdir(3), telldir(3)