mkdir()

Create a subdirectory

Synopsis:

#include <sys/types.h>
#include <sys/stat.h>

int mkdir( const char *path,
           mode_t mode );

Arguments:

path

The name of the directory that you want to create.

mode

The permissions for the directory, modified by the process's file-creation mask (see umask()).

The access permissions for the file or directory are specified as a combination of bits defined in the <sys/stat.h> header file. For more information, see the description of the st_mode member of the stat structure in the entry for stat().

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The mkdir() function creates a new subdirectory named path. The path can be relative to the current working directory or it can be an absolute path name.

---

Not all filesystems support the creation of directories. For example, /dev/shmem (which really isn't a filesystem but looks like one) doesn't. For more information, see the Working with Filesystems chapter of the QNX Neutrino User's Guide.

---

The directory's owner ID is set to the process's effective user ID. The directory's group ID is set to the group ID of the parent directory (if the parent set-group ID bit is set) or to the process's effective group ID.

The newly created directory is empty.

The following bits, in addition to file permission bits, behave as follows:

S_ISGID

Files and directories created within this directory have the group ID of this directory instead of the group ID of the process creating the file or directory.

S_ISVTX

Files can be removed or renamed only if one or more of the following is true:

• The user owns the file.
• The user owns the directory.
• The file is writable by the user.
• The user is privileged.

The mkdir() function marks the st_atime, st_ctime, and st_mtime fields of the directory for update. Also, the st_ctime and st_mtime fields of the parent directory are also updated.

Returns:

0, or -1 if an error occurs (errno is set).

Errors:

EACCES

Search permission is denied for a component of path, or write permission is denied on the parent directory of path.

EEXIST

The directory named by path already exists.

ELOOP

Too many levels of symbolic links.

EMLINK

The link count of the parent directory would exceed LINK_MAX.

ENAMETOOLONG

The length of path exceeds PATH_MAX, or a pathname component is longer than NAME_MAX.

ENOENT

A pathname component in the specified path doesn't exist, or path is an empty string.

ENOSPC

The filesystem doesn't contain enough space to hold the contents of the new directory or to extend the parent directory, or the maximum limit of files and directories has been reached.

ENOSYS

This function isn't supported for this path.

ENOTDIR

A component of path isn't a directory.

EROFS

The parent directory resides on a read-only filesystem.

Examples:

To make a new directory called /src in /hd:

#include <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h>

int main( void )
{
    (void)mkdir( "/hd/src",
                 S_IRWXU |
                 S_IRGRP | S_IXGRP |
                 S_IROTH | S_IXOTH );

    return EXIT_SUCCESS;
}

Classification:

POSIX 1003.1

See also:

chdir(), chmod(), errno, fchdir(), getcwd(), mknod(), rmdir(), stat(), umask()