man opendir (3): open a directory

Other Alias

fdopendir

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:: _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: The per-process limit on the number of open file descriptors has been reached.
ENFILE: The system-wide limit on the total number of open files has been reached.
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.

ATTRIBUTES

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

Interface	Attribute	Value
opendir(), fdopendir()	Thread safety	MT-Safe

CONFORMING TO

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

NOTES

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.

COLOPHON

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