.\" This manpage is Copyright (C) 1992 Drew Eckhardt; .\" and Copyright (C) 1993 Michael Haardt .\" and Copyright (C) 1993,1994 Ian Jackson .\" and Copyright (C) 2006, 2014 Michael Kerrisk .\" .\" %%%LICENSE_START(GPL_NOVERSION_ONELINE) .\" You may distribute it under the terms of the GNU General .\" Public License. It comes with NO WARRANTY. .\" %%%LICENSE_END .\" .TH MKDIR 2 2016-03-15 "Linux" "Linux Programmer's Manual" .SH NAME mkdir, mkdirat \- create a directory .SH SYNOPSIS .nf .B #include .B #include .\" .B #include .sp .BI "int mkdir(const char *" pathname ", mode_t " mode ); .sp .BR "#include " "/* Definition of AT_* constants */" .B #include .sp .BI "int mkdirat(int " dirfd ", const char *" pathname ", mode_t " mode ); .fi .sp .in -4n Feature Test Macro Requirements for glibc (see .BR feature_test_macros (7)): .in .sp .BR mkdirat (): .PD 0 .ad l .RS 4 .TP 4 Since glibc 2.10: _POSIX_C_SOURCE\ >=\ 200809L .TP Before glibc 2.10: _ATFILE_SOURCE .RE .ad .PD .fi .SH DESCRIPTION .BR mkdir () attempts to create a directory named .IR pathname . The argument .I mode specifies the mode for the new directory (see .BR stat (2)). It is modified by the process's .I umask in the usual way: in the absence of a default ACL, the mode of the created directory is .RI ( mode " & ~" umask " & 0777)." Whether other .I 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 .RI ( "mount -o bsdgroups" or, synonymously .IR "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. .\" .\" .SS mkdirat() The .BR mkdirat () system call operates in exactly the same way as .BR mkdir (), except for the differences described here. If the pathname given in .I pathname is relative, then it is interpreted relative to the directory referred to by the file descriptor .I dirfd (rather than relative to the current working directory of the calling process, as is done by .BR mkdir () for a relative pathname). If .I pathname is relative and .I dirfd is the special value .BR AT_FDCWD , then .I pathname is interpreted relative to the current working directory of the calling process (like .BR mkdir ()). If .I pathname is absolute, then .I dirfd is ignored. .PP See .BR openat (2) for an explanation of the need for .BR mkdirat (). .SH RETURN VALUE .BR mkdir () and .BR mkdirat () return zero on success, or \-1 if an error occurred (in which case, .I errno is set appropriately). .SH ERRORS .TP .B EACCES The parent directory does not allow write permission to the process, or one of the directories in .I pathname did not allow search permission. (See also .BR path_resolution (7).) .TP .B EDQUOT The user's quota of disk blocks or inodes on the filesystem has been exhausted. .TP .B EEXIST .I pathname already exists (not necessarily as a directory). This includes the case where .I pathname is a symbolic link, dangling or not. .TP .B EFAULT .IR pathname " points outside your accessible address space." .TP .B ELOOP Too many symbolic links were encountered in resolving .IR pathname . .TP .B EMLINK The number of links to the parent directory would exceed .BR LINK_MAX . .TP .B ENAMETOOLONG .IR pathname " was too long." .TP .B ENOENT A directory component in .I pathname does not exist or is a dangling symbolic link. .TP .B ENOMEM Insufficient kernel memory was available. .TP .B ENOSPC The device containing .I pathname has no room for the new directory. .TP .B ENOSPC The new directory cannot be created because the user's disk quota is exhausted. .TP .B ENOTDIR A component used as a directory in .I pathname is not, in fact, a directory. .TP .B EPERM The filesystem containing .I pathname does not support the creation of directories. .TP .B EROFS .I pathname refers to a file on a read-only filesystem. .PP The following additional errors can occur for .BR mkdirat (): .TP .B EBADF .I dirfd is not a valid file descriptor. .TP .B ENOTDIR .I pathname is relative and .I dirfd is a file descriptor referring to a file other than a directory. .SH VERSIONS .BR mkdirat () was added to Linux in kernel 2.6.16; library support was added to glibc in version 2.4. .SH CONFORMING TO .BR mkdir (): SVr4, BSD, POSIX.1-2001, POSIX.1-2008. .\" SVr4 documents additional EIO, EMULTIHOP .BR mkdirat (): POSIX.1-2008. .SH NOTES Under Linux, apart from the permission bits, the .B S_ISVTX .I mode bit is also honored. .PP There are many infelicities in the protocol underlying NFS. Some of these affect .BR mkdir (). .SS Glibc notes On older kernels where .BR mkdirat () is unavailable, the glibc wrapper function falls back to the use of .BR mkdir (). When .I pathname is a relative pathname, glibc constructs a pathname based on the symbolic link in .IR /proc/self/fd that corresponds to the .IR dirfd argument. .SH SEE ALSO .BR mkdir (1), .BR chmod (2), .BR chown (2), .BR mknod (2), .BR mount (2), .BR rmdir (2), .BR stat (2), .BR umask (2), .BR unlink (2), .BR acl (5) .BR path_resolution (7) .SH COLOPHON This page is part of release 4.10 of the Linux .I man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at \%https://www.kernel.org/doc/man\-pages/.