function ExtractFileDrive ( const FullFileName : string ) : string; 
 
 
Description 
The ExtractFileDrive function extracts from FullFileName the drive substring. 
 
If the file name does not contain a drive prefix, then an empty string is returned. 
 
Related commands 
ChangeFileExt Change the extension part of a file name 
ExtractFileDir Extracts the dir part of a full file name 
ExtractFileExt Extracts the extension part of a full file name 
ExtractFileName Extracts the name part of a full file name 
ExtractFilePath Extracts the path part of a full file name 
ProcessPath Split a drive/path/filename string into its constituent parts 
 
 Example code : Extract all of the parts of a full file name 
var
 fullFileName : string;
begin
 // Set up a full file name with drive and path
 fullFileName := 'C:\Program Files\Borland\Delphi7\Projects\Unit1.dcu';
 // Show the component parts of this full name
 ShowMessage('Drive = '+ExtractFileDrive (fullFileName));
 ShowMessage('Dir = '+ExtractFileDir (fullFileName));
 ShowMessage('Path = '+ExtractFilePath (fullFileName));
 ShowMessage('Name = '+ExtractFileName (fullFileName));
 ShowMessage('Ext = '+ExtractFileExt (fullFileName));
end;
 
Show full unit code 
 Drive = C:
 Dir = C:\Program Files\Borland\Delphi7\Projects
 Path = C:\Program Files\Borland\Delphi7\Projects\
 Name = Unit1.dcu
 Ext = .dcu