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

Return type: String sink Returns: An OmniMark output object to the opened file.

Declaration

export external string sink function writer
        of      value file file-ref

Argument definitions

file-ref

The vfs.file object associated with the file to be written to.

You can use vfs.writer to attach an OmniMark stream to a file so that you can send output to that file. In the following program, vfs.open is used to open the file notes.txt. Then vfs.writer is used to attach the open file to an OmniMark stream for writing:

  import "omvfs.xmd" prefixed by vfs.
  
  process
    local vfs.file output-file
    set output-file to vfs.open "/temp/notes.txt"
       for vfs.read-write-mode
    using output as vfs.writer of output-file
       submit #main-input
       ;data is written by find rules

If your program is running in an environment where other programs may be accessing the file you are writing to, it is advisable to lock the file while writing:

  import "omvfs.xmd" prefixed by vfs.
  
  process
    local vfs.file output-file
    set output-file to vfs.open "/temp/Notes.txt"
       for vfs.read-write-mode
    vfs.lock output-file
    using output as vfs.writer of output-file
       submit #main-input
       ;data is written by find rules
    vfs.unlock output-file

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
• VFS206 The file 'X' must be opened with write access to enable writing to it
• VFS217 The function timed out before the lock could be obtained on 'X'
• VFS300 Generic operating system error

Related Syntax    vfs.open    vfs.lock    vfs.unlock    vfs.reader    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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