Error message caused into to the microstation v8i s3

Question

Hello, 
 We are a company that uses MICROSTATION software to deploy our own solution &ldquo;Dkm&egrave;tre&rdquo; that we have developed with the C and MDL languages. 
 Our solution operates correctly with the series 1 and 2 of the MICROSTATION v8i version, but updating MICROSTATION to the series 3 generates some bugs in the Dkm&egrave;tre solution. 
 These bugs occur as a message error when we modify the content of components as Text component, combo box component... 
 You will find attached a screen capture of the error message. 
 So, I'd like to have some details about these bugs. 
 Cordially.

Jon Summers · Accepted Answer

Unknown said: I don&rsquo;t think that this bug is due to the values of the dgnModeleRef and the idNiveau variables 
 You're assuming that SS1 and SS3 behave the same way when it encounters a NULL model ref. Since your question is all about differences between SS1 and SS3, why not follow the advice you've been given? 
 I repeat, a NULL DgnModelRefP pointer is not valid. It's faster to write ACTIVEMODEL in your code than to post a question here.

Michael Stark · Answer

No matter what you think, a value of 0 (NULL) for a dgnModelRef is never valid, as a dereference of such a pointer will always end up with a failure of unallowed memory access. 
 It was often enough said that the old way of delivering NULL for a DgnModelRefP, that was implemented for whatever reason (maybe easier rewriting of V7 apps), has to be overcome and each function that is touched will no longer accept a NULL pointer. Maybe mdlView_setLevelDisplay worked in way where a NULL pointer was previously automatically switched into a usage of ACTIVEMODEL. But there where strong hints that this behaviour might still work in some functions, but is not so by design, and maybe broken without any further notice. 
 Provide a valid dgnModelRefP (i.e. by using the macro ACTIVEMODEL) and I expect your problem to be gone. If not, we can try to analyze some of your code, but you have to provide some excerpt than.

cdiTech · Answer

Hello, 
 So I replace the dgnModelRefP with ACTIVEMODEL and it works now. 
 Thank you for your help 
 
 I am a beginner on mdl and I need a tutorial other than Microstation V8 mdl function reference. So if you have one I will be very grateful