How do I determine the Version number of a DLL?
lazarus / 34-Windows

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RedOctober · 2021-12-24 20:05

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.

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MarkMLl · 2021-12-24 20:54

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

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trev · 2021-12-24 21:39

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

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RedOctober · 2021-12-25 00:11

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][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i  uses 
FileUtil, fileinfo, winpeimagereader; ... type  TDllInfo =
class(TObject)    FileName : String;    ModulName : String;    Info :
string;  end;  ...  function GetDLLVer(const dll_fnm: String):
String; ... implementation  ...  function GetDLLVer(const dll_fnm:
String): String;var  i: Integer;  FileVerInfo:TFileVersionInfo; 
FileName, ModulName: String;  aDllInfo : TDllInfo;begin  FileVerInfo
:= nil;  try    FileVerInfo:= TFileVersionInfo.Create(nil);   
FileVerInfo.FileName:= dll_fnm;    try      FileVerInfo.ReadFileInfo; 
    ModulName:= FileVerInfo.VersionStrings.Values['InternalName'];   
 if ModulName <> '' then begin        aDllInfo := TDllInfo.Create;   
   aDllInfo.FileName:= dll_fnm;        aDllInfo.ModulName:=
ModulName;        aDllInfo.Info :=
FileVerInfo.VersionStrings.Values['FileVersion'];        Result :=
aDllInfo.Info;      end;    finally      ; // nothing to do    end; 
finally    FileVerInfo.Free;  end;end;