vfs.open-file-system

function

Library: File system utilities (OMVFS)
Import : omvfs.xmd

Returns: A VFS file object for the opened file.

Declaration

export external file function open-file-system
                value string filename
        on      value directory on-dir optional
        for     value integer access-type optional initial {read-mode}

Argument definitions

filename: The path to the file to be opened.

on-dir: A connected vfs.directory object. If this parameter is specified the filename parameter is interpreted relative to the vfs.directory and must be expressed as a relative URL.

access-type: An integer constant signifying the desired mode of access. The default value is vfs.read-mode.

Purpose

You can use vfs.open-file-system to open a file. vfs.open-file-system creates a vfs.file object that represents the file, and which can be used with various OMVFS functions to manipulate the file.

You may specify the mode in which the file is opened. The default mode is read mode. The following modes are available:

vfs.read-mode - open the file in read-only mode. You can only read from the file.
vfs.write-mode - allows only writing to the file. File is truncated to byte 0 when opened.
vfs.read-write-mode - allows for both reading and writing to the file. The cursor is positioned at the first byte of the file.
vfs.read-write-append-mode - allows both reading and writing of the file. The cursor is positioned after the last byte of the file.
vfs.write-append-mode - file opened for writing only. The cursor is positioned after the last byte of the file.

This function is identical to vfs.open except that non-file URLs are not supported.

Exceptions

The following exceptions may occur:

VFS001 The requested function is not supported for the type of connection
VFS004 The specified name 'X' exceeds system length limits
VFS100 The vfsDir object must be connected before it can be used
VFS105 The path 'X' is not a valid absolute or relative path
VFS111 The URL 'X' contains invalid encoding
VFS201 An invalid value was specified for the file access
VFS300 Generic operating system error
VFS306 The file 'X' does not exist