NAME

       dirfd - get directory stream file descriptor

SYNOPSIS

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

       int dirfd(DIR *dirp);

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

       dirfd():
           _BSD_SOURCE || _SVID_SOURCE
           || /* Since glibc 2.10: */
               (_POSIX_C_SOURCE >= 200809L || _XOPEN_SOURCE >= 700)

DESCRIPTION

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

       This  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,  a  nonnegative  file descriptor is returned.  On error, -1 is returned, and errno is set to
       indicate the cause of 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

   Multithreading (see pthreads(7))
       The dirfd() function is thread-safe.

CONFORMING TO

       POSIX.1-2008.  This function was a BSD extension, present in 4.3BSD-Reno, not in 4.2BSD.

NOTES

       The prototype for dirfd() is available only if _BSD_SOURCE or _SVID_SOURCE is defined.

SEE ALSO

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

COLOPHON

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       information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.