dirfd()

Updated: May 06, 2022

Extract the file descriptor for a DIR stream

Synopsis:

#include <dirent.h>

int dirfd( DIR *dirp );

Arguments:

dirp
The DIR stream (directory) to extract the file descriptor from.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The dirfd() function returns a file descriptor referring to the DIR stream (directory) indicated by the dirp argument. You can use this file descriptor with any of the *at() functions.

If an attempt is made to close the file descriptor or modify the state of the associated description, other than by calling the functions closedir(), readdir(), readdir_r(), rewinddir(), or seekdir(), the behavior is undefined.

Call closedir() to close the DIR stream; this also closes the file descriptor.

Returns:

A file descriptor for the stream, or -1 if an error occurred (errno is set).

Errors:

EINVAL
The dirp argument doesn't refer to a valid DIR stream.

Classification:

POSIX 1003.1

Safety:  
Cancellation point No
Interrupt handler No
Signal handler Yes
Thread Yes