.\" This manpage is Copyright (C) 1992 Drew Eckhardt;
-.\" 1993 Michael Haardt
-.\" 1993,1994 Ian Jackson.
+.\" 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 2013-01-27 "Linux" "Linux Programmer's Manual"
+.TH MKDIR 2 2014-08-19 "Linux" "Linux Programmer's Manual"
.SH NAME
-mkdir \- create a directory
+mkdir, mkdirat \- create a directory
.SH SYNOPSIS
.nf
.B #include <sys/stat.h>
.\" .B #include <unistd.h>
.sp
.BI "int mkdir(const char *" pathname ", mode_t " mode );
+.sp
+.BR "#include <fcntl.h> " "/* Definition of AT_* constants */"
+.B #include <sys/stat.h>
+.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:
+_XOPEN_SOURCE\ >=\ 700 || _POSIX_C_SOURCE\ >=\ 200809L
+.TP
+Before glibc 2.10:
+_ATFILE_SOURCE
+.RE
+.ad
+.PD
.fi
.SH DESCRIPTION
.BR mkdir ()
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 file system is mounted with BSD group semantics
+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
+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 ()
-returns zero on success, or \-1 if an error occurred (in which case,
+and
+.BR mkdirat ()
+return zero on success, or \-1 if an error occurred (in which case,
.I errno
is set appropriately).
.SH ERRORS
.BR path_resolution (7).)
.TP
.B EDQUOT
-The user's quota of disk blocks or inodes on the file system has been
+The user's quota of disk blocks or inodes on the filesystem has been
exhausted.
.TP
.B EEXIST
is not, in fact, a directory.
.TP
.B EPERM
-The file system containing
+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 file system.
+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
-SVr4, BSD, POSIX.1-2001.
+.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, only the
+Under Linux, apart from the permission bits, only the
.B S_ISVTX
mode bit is honored.
That is, under Linux the created directory actually gets mode
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 mkdirat (2),
.BR mknod (2),
.BR mount (2),
.BR rmdir (2),
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