https://forge.codesys.com/forge/talk/Engineering/thread/b7bbfab06c/2020-02-27T14:12:01.123000ZRecent posts to Communication between Libraries with pointer2020-02-27T14:12:01.123000Z2020-02-27T14:12:01.123000ZAnonymoushttps://forge.codesys.com/u/*anonymous/https://forge.codesys.comc7a1cbfcc4582b47dce068b617c96a9fb9542098

<div class="markdown_content"><p><em>Originally created by:</em> scott_cunningham</p> <p>Instead of trying to pass a pointer, try having your library 2 require library 1. Then from within library 2, you can call any PRGs or FBs in library1.</p></div>

2020-02-27T14:12:00.783000Z2020-02-27T14:12:00.783000Zrickjhttps://forge.codesys.com/u/rickj/https://forge.codesys.com07970cd76f72b2ced5bd41047b9a9188045a3794

<div class="markdown_content"><p>The error list you show looks, to me, like a compiler crash. Also isn't "GVL" a reserved word?</p></div>

2020-02-27T14:12:00.387000Z2020-02-27T14:12:00.387000ZAnonymoushttps://forge.codesys.com/u/*anonymous/https://forge.codesys.com89508417a2d6e232fc0494a79fa8c95676550771

<div class="markdown_content"><p><em>Originally created by:</em> KevinR</p> <p>Welcome to the community,</p> <p>sorry - but your question is hard to understand. Maybe it helps, if you can post all of your code or upload an example project. </p> <p>Best Regards,<br/> Kevin</p></div>

2020-02-27T14:11:59.301000Z2020-02-27T14:11:59.301000ZRon123https://forge.codesys.com/u/ron123/https://forge.codesys.comcc2196b766918861aa3f7a67c1d22eb9d52fe0b2

<div class="markdown_content"><p>Maybe I have to explain my problem a little bit more... <br/> This is how my program looks like:</p> <p><strong>Library1:</strong><br/> Logging.prg</p> <p><strong>Library2:</strong><br/> GVL holds the pointer:<br/> pLog : pointer to Library1.Logging();</p> <p>Program.prg with M_DoSomething().<br/> Inside the method the foloowing code exists:<br/> pLog^.Fatal('Caller','LogMsg');</p> <p><strong>Main.prg:</strong><br/> 1. Set the pointer to Library2: "Library2.Initialize(pLog := ADR(Library1.Logging());"<br/> 2. Execute "Library2.Program();"<br/> 3. call: "Library2.M_DoSomething();)</p> <p>The error comes while building the solution as soon as I implement the execution "Library2.Program();" or call "Library2.M_DoSomething();).<br/> If i do not implment this into main, there is no compiling error.</p></div>

2020-02-27T14:11:58.944000Z2020-02-27T14:11:58.944000ZRon123https://forge.codesys.com/u/ron123/https://forge.codesys.comf7a3574761ace25f31e66a2d36baa144d966838b

<div class="markdown_content"><p>Hi<br/> I am trying to establisch a communication between 2 of my libs using TwinCat 3 Built 4020.10. <br/> For that I tried to pass a pointer to a program of lib1 to lib 2 and save it there.</p> <p>But during built of the program which is using both libs I get the following error #3580:<br/> "Internal error in _IStatement (maybe try to simplify expressions): GVL.pLog^.Fatal(Caller:=sFuncName,Msg:=strLogMsg): <br/> System.NullReferenceException: ..."</p> <p>By the way the above line of code is inside lib 2 and "pLog" is the pointer i passed to lib2...</p> <p>Any ideas?<br/> Thanks!</p> <p><img alt="IMG: built error3580.jpg" rel="nofollow" src="https://forum.codesys.com//download/file.php?id=2083"/></p></div>