Directories are created with the
mkdir function. (There is also
a shell command
mkdir which does the same thing.)
mkdirfunction creates a new, empty directory with name filename.
The argument mode specifies the file permissions for the new directory file. See Permission Bits, for more information about this.
A return value of
0indicates successful completion, and
-1indicates failure. In addition to the usual file name syntax errors (see File Name Errors), the following
errnoerror conditions are defined for this function:
- Write permission is denied for the parent directory in which the new directory is to be added.
- A file named filename already exists.
- The parent directory has too many links (entries).
Well-designed file systems never report this error, because they permit more links than your disk could possibly hold. However, you must still take account of the possibility of this error, as it could result from network access to a file system on another machine.
- The file system doesn't have enough room to create the new directory.
- The parent directory of the directory being created is on a read-only file system and cannot be modified.