mkdir(2) — Linux manual page


MKDIR(2)                  Linux Programmer's Manual                 MKDIR(2)

NAME         top

       mkdir, mkdirat - create a directory

SYNOPSIS         top

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

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

       #include <fcntl.h>           /* Definition of AT_* constants */
       #include <sys/stat.h>

       int mkdirat(int dirfd, const char *pathname, mode_t mode);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

           Since glibc 2.10:
               _POSIX_C_SOURCE >= 200809L
           Before glibc 2.10:

DESCRIPTION         top

       mkdir() attempts to create a directory named pathname.

       The argument mode specifies the mode for the new directory (see
       inode(7)).  It is modified by the process's umask in the usual way:
       in the absence of a default ACL, the mode of the created directory is
       (mode & ~umask & 0777).  Whether other mode bits are honored for the
       created directory depends on the operating system.  For Linux, see
       NOTES below.

       The newly created directory will be owned by the effective user ID of
       the process.  If the directory containing the file has the set-group-
       ID bit set, or if the filesystem is mounted with BSD group semantics
       (mount -o bsdgroups or, synonymously mount -o grpid), the new
       directory will inherit the group ownership from its parent; otherwise
       it will be owned by the effective group ID of the process.

       If the parent directory has the set-group-ID bit set, then so will
       the newly created directory.

       The mkdirat() system call operates in exactly the same way as
       mkdir(), except for the differences described here.

       If the pathname given in pathname is relative, then it is interpreted
       relative to the directory referred to by the file descriptor dirfd
       (rather than relative to the current working directory of the calling
       process, as is done by mkdir() for a relative pathname).

       If pathname is relative and dirfd is the special value AT_FDCWD, then
       pathname is interpreted relative to the current working directory of
       the calling process (like mkdir()).

       If pathname is absolute, then dirfd is ignored.

       See openat(2) for an explanation of the need for mkdirat().

RETURN VALUE         top

       mkdir() and mkdirat() return zero on success, or -1 if an error
       occurred (in which case, errno is set appropriately).

ERRORS         top

       EACCES The parent directory does not allow write permission to the
              process, or one of the directories in pathname did not allow
              search permission.  (See also path_resolution(7).)

       EDQUOT The user's quota of disk blocks or inodes on the filesystem
              has been exhausted.

       EEXIST pathname already exists (not necessarily as a directory).
              This includes the case where pathname is a symbolic link,
              dangling or not.

       EFAULT pathname points outside your accessible address space.

       EINVAL The final component ("basename") of the new directory's
              pathname is invalid (e.g., it contains characters not
              permitted by the underlying filesystem).

       ELOOP  Too many symbolic links were encountered in resolving

       EMLINK The number of links to the parent directory would exceed

              pathname was too long.

       ENOENT A directory component in pathname does not exist or is a
              dangling symbolic link.

       ENOMEM Insufficient kernel memory was available.

       ENOSPC The device containing pathname has no room for the new

       ENOSPC The new directory cannot be created because the user's disk
              quota is exhausted.

              A component used as a directory in pathname is not, in fact, a

       EPERM  The filesystem containing pathname does not support the
              creation of directories.

       EROFS  pathname refers to a file on a read-only filesystem.

       The following additional errors can occur for mkdirat():

       EBADF  dirfd is not a valid file descriptor.

              pathname is relative and dirfd is a file descriptor referring
              to a file other than a directory.

VERSIONS         top

       mkdirat() was added to Linux in kernel 2.6.16; library support was
       added to glibc in version 2.4.

CONFORMING TO         top

       mkdir(): SVr4, BSD, POSIX.1-2001, POSIX.1-2008.

       mkdirat(): POSIX.1-2008.

NOTES         top

       Under Linux, apart from the permission bits, the S_ISVTX mode bit is
       also honored.

       There are many infelicities in the protocol underlying NFS.  Some of
       these affect mkdir().

   Glibc notes
       On older kernels where mkdirat() is unavailable, the glibc wrapper
       function falls back to the use of mkdir().  When pathname is a
       relative pathname, glibc constructs a pathname based on the symbolic
       link in /proc/self/fd that corresponds to the dirfd argument.

SEE ALSO         top

       mkdir(1), chmod(2), chown(2), mknod(2), mount(2), rmdir(2), stat(2),
       umask(2), unlink(2), acl(5), path_resolution(7)

COLOPHON         top

       This page is part of release 5.09 of the Linux man-pages project.  A
       description of the project, information about reporting bugs, and the
       latest version of this page, can be found at

Linux                            2020-06-09                         MKDIR(2)

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