dirfd(3) — Linux manual page

dirfd(3)                Library Functions Manual                dirfd(3)

NAME

       dirfd - get directory stream file descriptor

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

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

       int dirfd(DIR *dirp);

   Feature Test Macro Requirements for glibc (see
   feature_test_macros(7)):

       dirfd():
           /* Since glibc 2.10: */ _POSIX_C_SOURCE >= 200809L
               || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

DESCRIPTION

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

       This file descriptor is the one used internally by the directory
       stream.  As a result, it is useful only 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.

RETURN VALUE

       On success, dirfd() returns a file descriptor (a nonnegative
       integer).  On error, -1 is returned, and errno is set to indicate
       the error.

ERRORS

       POSIX.1-2008 specifies two errors, neither of which is returned
       by the current implementation.

       EINVAL dirp does not refer to a valid directory stream.

       ENOTSUP
              The implementation does not support the association of a
              file descriptor with a directory.

ATTRIBUTES

       For an explanation of the terms used in this section, see
       attributes(7).
       ┌─────────────────────────────────────┬───────────────┬─────────┐
       │ Interface                           │ Attribute     │ Value   │
       ├─────────────────────────────────────┼───────────────┼─────────┤
       │ dirfd()                             │ Thread safety │ MT-Safe │
       └─────────────────────────────────────┴───────────────┴─────────┘

STANDARDS

       POSIX.1-2008.

HISTORY

       4.3BSD-Reno (not in 4.2BSD).

SEE ALSO

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

COLOPHON

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Linux man-pages 6.9.1          2024-05-02                       dirfd(3)

Pages that refer to this page: open(2), opendir(3), readdir(3)

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