OPENDIR(3)                                                              Linux Programmer's Manual                                                             OPENDIR(3)

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:
               _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 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 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-ex‐
       ec 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)

GNU                                                                            2021-03-22                                                                     OPENDIR(3)