opendir(3) Library Functions Manual opendir(3)
NAME
opendir, fdopendir - open a directory
LIBRARY
Standard C library (libc, -lc)
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 direc-
tory stream. On error, NULL is returned, and errno is set to indicate
the error.
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 since glibc 2.4.
ATTRIBUTES
For an explanation of the terms used in this section, see at-
tributes(7).
┌────────────────────────────────────────────┬───────────────┬─────────┐
│Interface │ Attribute │ Value │
├────────────────────────────────────────────┼───────────────┼─────────┤
│opendir(), fdopendir() │ Thread safety │ MT-Safe │
└────────────────────────────────────────────┴───────────────┴─────────┘
STANDARDS
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 de-
scriptor 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)
Linux man-pages 6.03 2022-12-15 opendir(3)
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