How do I determine the Version number of a DLL?

[RedOctober]

Platform:  OS: Windows Server 2016    Lazarus 2.0.10   FPC   3.2.0
I'm working with several different versions of a DLL.  The file name is always the same.  I have a Windows app, with a main form, and I'd like to display the version number of the DLL in use, on the main form, in a Label.  I cannot find a function that can extract this information.

Does anyone know of a function or code snippet that can accomplish this?  Thanks in advance.

[MarkMLl]

In the general case, can't be done. It would have to rely on the DLL author exporting a function (etc.) which declared the version number.

I've done quite a lot of custom hacking based on a DLL (or on Linux, shared object) exporting a magic number which defined the programming interface, but that relies on having full control of both the DLL and the program that's using it.

MarkMLl

[trev]

See the Forum thread FileVersionInfo did not work with a DLL for the solution.

[RedOctober]

Hi MarkMLI and Trev.  Thanks to your help, I was able to modify the code shown in the other examples, to determine the version of a single DLL, which is what I need. The code below works.

Code: Pascal  [Select][+][-]

1.  
2. uses
3.   FileUtil, fileinfo, winpeimagereader;
4.  
5. ...
6.  
7. type
8.   TDllInfo = class(TObject)
9.     FileName : String;
10.     ModulName : String;
11.     Info : string;
12.   end;
13.  
14. ...
15.  
16.  
17. function GetDLLVer(const dll_fnm: String): String;
18.  
19. ...
20.  
21. implementation
22.  
23. ...
24.  
25.  
26. function GetDLLVer(const dll_fnm: String): String;
27. var
28.   i: Integer;
29.   FileVerInfo:TFileVersionInfo;
30.   FileName, ModulName: String;
31.   aDllInfo : TDllInfo;
32. begin
33.   FileVerInfo := nil;
34.   try
35.     FileVerInfo:= TFileVersionInfo.Create(nil);
36.     FileVerInfo.FileName:= dll_fnm;
37.     try
38.       FileVerInfo.ReadFileInfo;
39.       ModulName:= FileVerInfo.VersionStrings.Values['InternalName'];
40.       if ModulName <> '' then begin
41.         aDllInfo := TDllInfo.Create;
42.         aDllInfo.FileName:= dll_fnm;
43.         aDllInfo.ModulName:= ModulName;
44.         aDllInfo.Info := FileVerInfo.VersionStrings.Values['FileVersion'];
45.         Result := aDllInfo.Info;
46.       end;
47.     finally
48.       ; // nothing to do
49.     end;
50.   finally
51.     FileVerInfo.Free;
52.   end;
53. end;
54.  
55.  
56.