file_spec

    A pointer to a string that contains a valid OpenVMS or UNIX
    style file specification. After the function call, the given
    file pointer is associated with this file.

 a_mode

    The access mode indicator. See the fopen function for a
    description.

 file_ptr

    A file pointer.

  . . .

    Optional file attribute arguments. The file attribute arguments
    are the same as those used in the creat function.