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@(#)mkdir.2 8.2 (Berkeley) 12/11/93
.Dd September 12, 2025 .Dt MKDIR 2 .Os .Sh NAME .Nm mkdir , .Nm mkdirat .Nd make a directory file .Sh LIBRARY .Lb libc .Sh SYNOPSIS n sys/stat.h .Ft int .Fn mkdir "const char *path" "mode_t mode" n sys/stat.h n fcntl.h .Ft int .Fn mkdirat "int fd" "const char *path" "mode_t mode" .Sh DESCRIPTION The directory .Fa path is created with the access permissions specified by .Fa mode and restricted by the .Xr umask 2 of the calling process. On .Nx all other mode bits .Dv ( S_ISUID , .Dv S_ISGID , .Dv S_ISTXT ) are ignored. This is implementation defined; for example on Linux .Dv S_ISTXT is honored.
p
.Fn mkdirat
works the same way as
.Fn mkdir
except if
.Fa path
is relative.
In that case, it is looked up from a directory whose file
descriptor was passed as
.Fa fd .
Search permission is required this directory.
(These alternatives await a decision about the semantics of O_SEARCH)
Search permission is required on this directory
except if
.Fa fd
was opened with the
.Dv O_SEARCH
flag.
- or -
This file descriptor must have been opened with the
.Dv O_SEARCH
flag.
.Fa fd
can be set to
.Dv AT_FDCWD
in order to specify the current directory.
p The directory's owner ID is set to the process's effective user ID. The directory's group ID is set to that of the parent directory in which it is created. .Sh RETURN VALUES .Rv -std mkdir mkdirat .Sh ERRORS Both .Fn mkdir and .Fn mkdirat will fail and no directory will be created if: l -tag -width Er t Bq Er EACCES Search permission is denied for a component of the path prefix. t Bq Er EDQUOT The new directory cannot be created because the user's quota of disk blocks on the file system that will contain the directory has been exhausted. Or, the user's quota of inodes on the file system on which the directory is being created has been exhausted. t Bq Er EEXIST The named file exists. t Bq Er EFAULT .Fa path points outside the process's allocated address space. t Bq Er EIO An I/O error occurred while making the directory entry or allocating the inode; or an I/O error occurred while reading from or writing to the file system. t Bq Er ELOOP Too many symbolic links were encountered in translating the pathname. t Bq Er EMLINK The new directory cannot be created because the parent directory contains too many subdirectories. t Bq Er ENAMETOOLONG A component of a pathname exceeded rq Dv NAME_MAX characters, or an entire path name exceeded rq Dv PATH_MAX characters. t Bq Er ENOENT A component of the path prefix does not exist. t Bq Er ENOSPC The new directory cannot be created because there is no space left on the file system that will contain the directory. Or, there are no free inodes on the file system on which the directory is being created. t Bq Er ENOTDIR A component of the path prefix is not a directory. t Bq Er EROFS The named file resides on a read-only file system. .El
p In addition, .Fn mkdirat will fail if: l -tag -width Er t Bq Er EBADF .Fa path does not specify an absolute path and .Fa fd is neither .Dv AT_FDCWD nor a valid file descriptor open for reading or searching. t Bq Er ENOTDIR .Fa path is not an absolute path and .Fa fd is a file descriptor associated with a non-directory file. .El .Sh SEE ALSO .Xr chmod 2 , .Xr stat 2 , .Xr umask 2 .Sh STANDARDS The .Fn mkdir function conforms to .St -p1003.1-90 . .Fn mkdirat conforms to .St -p1003.1-2008 . .Sh HISTORY The .Fn mkdir function appeared in .At v1 .
Indexes created Mon Sep 22 13:09:51 GMT 2025