The facilities described in this section let you read the contents of a directory file. This is useful if you want your program to list all the files in a directory, perhaps as part of a menu.
The opendir function opens a directory stream whose
elements are directory entries. Alternatively fdopendir can be
used which can have advantages if the program needs to have more
control over the way the directory is opened for reading. This
allows, for instance, to pass the O_NOATIME flag to
open.
You use the readdir function on the directory stream to
retrieve these entries, represented as struct dirent
objects. The name of the file for each entry is stored in the
d_name member of this structure. There are obvious parallels
here to the stream facilities for ordinary files, described in
Input/Output on Streams.