Library: File system utilities (OMVFS) legacy Include: omvfs.xin

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

Declaration

define external string sink function vfsWrite
     value  vfsFile  file

Argument definitions

file

is the vfsFile object associated with the file to be modified.

Use vfsWrite to obtain an output object (to write) to an open file.

Requirements

You must include the following line at the beginning of your OmniMark program:

  include "omvfs.xin"

file must

• be open (else external exception VFS200)
• have been opened with write access (else external exception VFS206)
• not be currently read from or written to (else external exception VFS204)
• not have lock (either shared or exclusive) placed on
  • the entire file, or
  • the portion of the file being written to
  by any other process (else external exception VFS217)

Usage Notes

The locking exception can be thrown at any point during writing (external exception VFS217).

External exception VFS300 is thrown for any general OS operation failure. The text accompanying the exception will contain details on the reason for the failure.

Example

This example shows appropriate steps to write to the file Notes.txt in the private directory.

1. Open a file with read-write access.
2. Lock the file to avoid an exception if the file is locked by another process.
3. Obtain an output object for the file.
4. Write to the file.
5. Unlock the file.

  include "omvfs.xin"
  
  process
    local vfsFile myFile
    local stream foo
  	. . .
    set myFile to vfsOpen "/private/Notes.txt" 
    	 for VFS-READ-WRITE
  	. . .
    vfsLock myFile
    open foo as vfsWrite myFile
    put foo "Write this to the specified file. %n"
    vfsUnlock myFile

Other Library Functions    vfsChangeDir    vfsChangeOwner    vfsChangePermissions    vfsClose    vfsConnect    vfsConnectDir    vfsCopy    vfsCursorPosition    vfsDeleteDir    vfsDeleteFile    vfsDescribe    vfsDescribeFile    vfsDir    vfsDirName    vfsDisconnect    vfsFile    vfsFileDir    vfsFileName    vfsIsVersionCompatible    vfsLibraryVersion    vfsLink    vfsList    vfsLock    vfsMakeDir    vfsMove    vfsMoveCursor    vfsOpen    vfsRead    vfsRename    vfsTruncate    vfsUnlock    vfsWrite

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