VMS Help  —  CRTL  mkdir
    Creates a directory.

    Format

      #include  <stat.h>

      int mkdir  (const char *dir_spec, mode_t mode); (ISO POSIX-1)

      int mkdir  (const char *dir_spec, mode_t mode, . . . );
                 (DEC C Extension)

1  –  Arguments

 dir_spec

    A valid OpenVMS or UNIX style directory specification that may
    contain a device name. For example:

    DBA0:[BAY.WINDOWS]     /*    OpenVMS      */
    /dba0/bay/windows      /*   UNIX style    */

    This specification cannot contain a node name, filename, file
    extension, file version, or a wildcard character. The same
    restriction applies to the UNIX style directory specifications.

 mode

    A file protection. See the chmod function in this section for
    information about the specific file protections.

    The file protection of the new directory is derived from the
    mode argument, the process's file protection mask (see the umask
    function), and the parent-directory default protections.

    In a manner consistent with the OpenVMS behavior for creating
    directories, mkdir never applies delete access to the directory.
    An application that needs to set delete access should use an
    explicit call to chmod to set write permission.

    See the Description section of this function for more information
    about how the file protection is set for the newly created
    directory.

  . . .

    Represents the following optional arguments. These arguments have
    fixed position in the argument list, and cannot be arbitrarily
    placed.

       unsigned int uic
       The user identification code (UIC) that identifies the
       owner of the created directory. If this argument is 0, the
       C RTL gives the created directory the UIC of the parent
       directory. If this argument is not specified, the C RTL
       gives the created directory your UIC. This optional argument
       is specific to the C RTL and is not portable.

       unsigned short max_versions
       The maximum number of file versions to be retained in the
       created directory. The system automatically purges the
       directory keeping, at most, max_versions number of every file.

       If this argument is 0, the C RTL does not place a limit
       on the maximum number of file versions.

       If this argument is not specified, the C RTL gives
       the created directory the default version limit of the parent
       directory.

       This optional argument is specific to the C RTL and is
       not portable.

       unsigned short r_v_number
       The volume (device) on which to place the created directory
       if the device is part of a volume set. If this argument is
       not specified, the C RTL arbitrarily places the created
       directory within the volume set. This optional argument is
       specific to the C RTL and is not portable.

2  –  Description

    If dir_spec specifies a path that includes directories, which
    do not exist, intermediate directories are also created.
    This differs from the behavior of the UNIX system where these
    intermediate directories must exist and will not be created.

    If you do not specify any optional arguments, the C RTL
    gives the directory your UIC and the default version limit of the
    parent directory, and arbitrarily places the directory within the
    volume set. You cannot get the default behavior for the uic or
    max_versions arguments if you specify any arguments after them.

                                   NOTE

       The way to create files with OpenVMS RMS default protections
       using the UNIX system-call functions umask, mkdir, creat,
       and open is to call mkdir, creat, and open with a file-
       protection mode argument of 0777 in a program that never
       specifically calls umask. These default protections include
       correctly establishing protections based on ACLs, previous
       versions of files, and so on.

       In programs that do vfork/exec calls, the new process image
       inherits whether umask has ever been called or not from
       the calling process image. The umask setting and whether
       the umask function has ever been called are both inherited
       attributes.

    The file protection supplied by the mode argument is modified by
    the process's file protection mask in such a way that the file
    protection for the new directory is set to the bitwise AND of the
    mode argument and the complement of the file protection mask.

    Default file protections are supplied to the new directory
    from the parent-directory such that if a protection value bit
    in the new directory is zero, then the value of this bit is
    inherited from the parent directory. However, bits in the parent
    directory's file protection that indicate delete access do not
    cause corresponding bits to be set in the new directory's file
    protection.

3  –  Return Values

    0                  Indicates success.
    -1                 Indicates failure.

4  –  Examples

    1.umask (0002); /* turn world write access off */

      mkdir ("sys$disk:[.parentdir.childdir]", 0222);
                                 /* turn write access on */

      Parent directory file protection: System:RWD, Owner:RWD,
                                           Group:R, World:R

      The file protection derived from the combination of the mode
      argument and the file protection mask set by umask is (0222)
      & ~(0002), which is 0220. When the parent directory defaults
      are applied to this protection, the protection for the new
      directory becomes:

        File protection:    System:RWD, Owner:RWD, Group:RWD, World:R

    2.umask (0000);

      mkdir ("sys$disk:[.parentdir.childdir]", 0444);
                                 /* turn read access on */

      Parent directory file protection: System:RWD, Owner:RWD,
                                          Group:RWD, World:RWD

      The file protection derived from the combination of the mode
      argument and the file protection mask set by umask is (0444)
      & ~(0000), which is 0444. When the parent directory defaults
      are applied to this protection, the protection for the new
      directory is:

        File protection:    System:RW, Owner:RW, Group:RW, World:RW

      Note that delete access is not inherited.
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