opendir man page

opendir, fdopendir — open a directory


#include <sys/types.h>

#include <dirent.h>

DIR *opendir(const char *name);
DIR *fdopendir(int fd);

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


Since glibc 2.10:
_POSIX_C_SOURCE >= 200809L
Before glibc 2.10:


The opendir() function opens a directory stream corresponding to the directory name, and returns a pointer to the directory stream. The stream is positioned at the first entry in the directory.

The fdopendir() function is like opendir(), but returns a directory stream for the directory referred to by the open file descriptor fd. After a successful call to fdopendir(), fd is used internally by the implementation, and should not otherwise be used by the application.

Return Value

The opendir() and fdopendir() functions return a pointer to the directory stream. On error, NULL is returned, and errno is set appropriately.


Permission denied.
fd is not a valid file descriptor opened for reading.
The per-process limit on the number of open file descriptors has been reached.
The system-wide limit on the total number of open files has been reached.
Directory does not exist, or name is an empty string.
Insufficient memory to complete the operation.
name is not a directory.


fdopendir() is available in glibc since version 2.4.


For an explanation of the terms used in this section, see attributes(7).

opendir(), fdopendir()Thread safetyMT-Safe

Conforming to

opendir() is present on SVr4, 4.3BSD, and specified in POSIX.1-2001. fdopendir() is specified in POSIX.1-2008.


Filename entries can be read from a directory stream using readdir(3).

The underlying file descriptor of the directory stream can be obtained using dirfd(3).

The opendir() function sets the close-on-exec flag for the file descriptor underlying the DIR *. The fdopendir() function leaves the setting of the close-on-exec flag unchanged for the file descriptor, fd. POSIX.1-200x leaves it unspecified whether a successful call to fdopendir() will set the close-on-exec flag for the file descriptor, fd.

See Also

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

Referenced By

closedir(3), dirfd(3), execve(2), explain(1), explain(3), explain_fdopendir(3), explain_fdopendir_or_die(3), explain_opendir(3), explain_opendir_or_die(3), fanotify_mark(2), fork(2), fts(3), getdirentries(3), gethugepagesizes(3), getpagesizes(3), glob(3), open(2), readdir(3), readdir.3am(3), rewinddir(3), scandir(3), seekdir(3), telldir(3).

Explore man page connections for opendir(3).

fdopendir(3) is an alias of opendir(3).