opendir(3) - Linux man page

Name

opendir, fdopendir - open a directory

Synopsis

#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)):

fdopendir():: Since glibc 2.10:; _XOPEN_SOURCE >= 700 || _POSIX_C_SOURCE >= 200809L; Before glibc 2.10:; _GNU_SOURCE

Description

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.

Errors

EACCES
Permission denied.
EBADF
fd is not a valid file descriptor opened for reading.
EMFILE
Too many file descriptors in use by process.
ENFILE
Too many files are currently open in the system.
ENOENT
Directory does not exist, or name is an empty string.
ENOMEM
Insufficient memory to complete the operation.
ENOTDIR: name is not a directory.

Versions

fdopendir() is available in glibc since version 2.4.

Conforming To

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

Notes

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.

Referenced By

execve(2), explain(1), explain(3), explain_opendir(3), explain_opendir_or_die(3), fork(2), fts(3), getdirentries(3), gethugepagesizes(3), getpagesizes(3), glob(3)