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

Declaration

  export external function move-cursor
          of      value file file-ref
          by      value integer offset optional
          to      value integer absolute optional

Argument definitions

file-ref

A vfs.file object representing the file in which the cursor is to be moved.

offset

The distance to move the cursor relative its current position.

absolute

The absolute position to move the cursor to.

You can use vfs.move-cursor to change the position at which the next read of a file will occur. The position may be specified either relative to the current cursor position, or as an absolute position in a file. For instance, if you know that the data you are interested in starts at byte 100 in a file, you can read from that position like this:

  import "omvfs.xmd" prefixed by vfs.

  process
     local vfs.file test-file
     set test-file
      to vfs.open "c:/omnimark/projects/testfile.txt"
     vfs.move-cursor of test-file to 100
     output vfs.reader of test-file

You must specify either a relative or absolute movement, and not both.

Exceptions

The following exceptions may occur:

• VFS200 The vfsFile object must be opened before it can be used
• VFS204 The file 'X' must not have an active output or source associated with it
• VFS209 An invalid value was specified for the absolute cursor movement
• VFS210 Absolute and relative cursor movement may not both be specified
• VFS211 The cursor cannot be positioned before the start of the file
• VFS300 Generic operating system error

Related Syntax    vfs.writer    vfs.cursor-position    vfs.file

Other Library Functions    vfs.change-directory    vfs.change-owner    vfs.change-permissions    vfs.close    vfs.connect    vfs.connect-directory    vfs.copy    vfs.cursor-position    vfs.default-certificates-file    vfs.delete-directory    vfs.delete-file    vfs.describe    vfs.describe-file    vfs.directory    vfs.directory-name    vfs.disconnect    vfs.file    vfs.file-directory    vfs.file-name    vfs.link    vfs.list    vfs.lock    vfs.make-directory    vfs.move    vfs.move-cursor    vfs.omvfs-version    vfs.open    vfs.open-file-system    vfs.open-ftp    vfs.open-http    vfs.open-https    vfs.reader    vfs.set-default-certificates-file    vfs.truncate    vfs.unlock    vfs.writer

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