mkdirat(2)

1mkdir(2)                      System Calls Manual                     mkdir(2)
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NAME

6       mkdir, mkdirat - create a directory
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LIBRARY

9       Standard C library (libc, -lc)
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SYNOPSIS

12       #include <sys/stat.h>
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14       int mkdir(const char *pathname, mode_t mode);
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16       #include <fcntl.h>           /* Definition of AT_* constants */
17       #include <sys/stat.h>
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19       int mkdirat(int dirfd, const char *pathname, mode_t mode);
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21   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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23       mkdirat():
24           Since glibc 2.10:
25               _POSIX_C_SOURCE >= 200809L
26           Before glibc 2.10:
27               _ATFILE_SOURCE
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DESCRIPTION

30       mkdir() attempts to create a directory named pathname.
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32       The  argument  mode  specifies  the mode for the new directory (see in‐
33       ode(7)).  It is modified by the process's umask in the  usual  way:  in
34       the  absence  of  a  default  ACL, the mode of the created directory is
35       (mode & ~umask & 0777).  Whether other mode bits are  honored  for  the
36       created  directory  depends  on  the  operating system.  For Linux, see
37       NOTES below.
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39       The newly created directory will be owned by the effective user  ID  of
40       the process.  If the directory containing the file has the set-group-ID
41       bit set, or if the filesystem  is  mounted  with  BSD  group  semantics
42       (mount -o bsdgroups or, synonymously mount -o grpid), the new directory
43       will inherit the group ownership from its parent; otherwise it will  be
44       owned by the effective group ID of the process.
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46       If  the parent directory has the set-group-ID bit set, then so will the
47       newly created directory.
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49   mkdirat()
50       The mkdirat() system call operates in exactly the same way as  mkdir(),
51       except for the differences described here.
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53       If  the  pathname given in pathname is relative, then it is interpreted
54       relative to the directory referred to  by  the  file  descriptor  dirfd
55       (rather  than  relative to the current working directory of the calling
56       process, as is done by mkdir() for a relative pathname).
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58       If pathname is relative and dirfd is the special value  AT_FDCWD,  then
59       pathname  is  interpreted  relative to the current working directory of
60       the calling process (like mkdir()).
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62       If pathname is absolute, then dirfd is ignored.
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64       See openat(2) for an explanation of the need for mkdirat().
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RETURN VALUE

67       mkdir() and mkdirat() return zero on success.  On error, -1 is returned
68       and errno is set to indicate the error.
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ERRORS

71       EACCES The  parent  directory  does  not  allow write permission to the
72              process, or one of the directories in  pathname  did  not  allow
73              search permission.  (See also path_resolution(7).)
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75       EBADF  (mkdirat())  pathname  is relative but dirfd is neither AT_FDCWD
76              nor a valid file descriptor.
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78       EDQUOT The user's quota of disk blocks or inodes on the filesystem  has
79              been exhausted.
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81       EEXIST pathname  already exists (not necessarily as a directory).  This
82              includes the case where pathname is a symbolic link, dangling or
83              not.
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85       EFAULT pathname points outside your accessible address space.
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87       EINVAL The final component ("basename") of the new directory's pathname
88              is invalid (e.g., it contains characters not  permitted  by  the
89              underlying filesystem).
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91       ELOOP  Too many symbolic links were encountered in resolving pathname.
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93       EMLINK The  number  of  links  to  the  parent  directory  would exceed
94              LINK_MAX.
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96       ENAMETOOLONG
97              pathname was too long.
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99       ENOENT A directory component in pathname does not exist or  is  a  dan‐
100              gling symbolic link.
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102       ENOMEM Insufficient kernel memory was available.
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104       ENOSPC The  device  containing  pathname has no room for the new direc‐
105              tory.
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107       ENOSPC The new directory cannot be  created  because  the  user's  disk
108              quota is exhausted.
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110       ENOTDIR
111              A  component  used as a directory in pathname is not, in fact, a
112              directory.
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114       ENOTDIR
115              (mkdirat()) pathname is relative and dirfd is a file  descriptor
116              referring to a file other than a directory.
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118       EPERM  The filesystem containing pathname does not support the creation
119              of directories.
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121       EROFS  pathname refers to a file on a read-only filesystem.
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VERSIONS

124       Under Linux, apart from the permission bits, the S_ISVTX  mode  bit  is
125       also honored.
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127   glibc notes
128       On  older  kernels  where  mkdirat()  is unavailable, the glibc wrapper
129       function falls back to the use of mkdir().  When pathname is a relative
130       pathname,  glibc  constructs  a  pathname based on the symbolic link in
131       /proc/self/fd that corresponds to the dirfd argument.
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STANDARDS

134       POSIX.1-2008.
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HISTORY

137       mkdir()
138              SVr4, BSD, POSIX.1-2001.
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140       mkdirat()
141              Linux 2.6.16, glibc 2.4.
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NOTES

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