> ----- Original Message ----- > From: "Walter Prins" <[EMAIL PROTECTED]> > To: [email protected] > Subject: Re: [delphi-en] Crystal 8 UDF's > Date: Thu, 16 Nov 2006 00:44:09 +0000 > > > Hello Paul, > > At the risk of belaboring this too much... :-) I think you might maybe > (?) still be making the same mistake I made (which prompted me to chip > in earlier on as well.) Notice, there are *2* PostMessage lines in your > code. The first one, happens **before** the line where n is assigned a > value. Thus, n is undefined for the first PostMessage, and as Rob's > pointed out, the compiler should've warned you about it. :-) > > Eg (quoting original code again, see lines marked with <<<<<<<<<<) : > > function LaunchApplication (ParamBlock : PUFParamBlock) : UFError; > var > ···Param1 : PUFParamListElement; //a pointer to the first parameter > ···n : integer; > ···fWakeup : Cardinal; > ···MyWakeup: PChar; > begin > ···//the first param is the AppID to launch > ···Param1 := GetParam (ParamBlock, 1); > > ···//check if the correct number of parameters is passed to our function > ···if (Param1 = nil) then > ···begin > ······MyWakeup := Error; > ······fWakeup := RegisterWindowMessage(MyWakeup); > ······If fWakeup <> 0 Then > ·········nResult := PostMessage(hWnd_BROADCAST, fWakeUp, n, n); > //<<<<<<<< n is undefined! > ······Result := UFNotEnoughParameters; > ······EXIT; > ···end; > > ···n := Param1.Parameter.ParamInteger; > ···MyWakeup := Wakeup; > ···fWakeup := RegisterWindowMessage(MyWakeup); > ···If fWakeup <> 0 Then > ······nResult := PostMessage(hWnd_BROADCAST, fWakeUp, n, n) // <<<<<< n > is defined here! > ···Else > ······nResult := False; > > ···ParamBlock^.ReturnValue.ReturnNumber := Param1.Parameter.ParamInteger; > ···Result := UFNoError; > end; > > Cheers > > Walter >
The first call to PostMessage only takes place if the Param1 variable is null, in which case the value on n is immaterial, it is a case of 'cut and paste' without checking what the code actually says! That said, the receiving application ignores the 'n' parameters received from the Error message. I think the problem is clearly with the method of passing parmaters from Crystal Reports to the dll. As I said earlier, this code was taken from an example of how to create UDFs in Delphi. So what I probably need is advise on how to create Crystal Reports UDFs in Delphi. Paul Bennett Experience is something you don't get until just after you need it. -- _______________________________________________ Surf the Web in a faster, safer and easier way: Download Opera 9 at http://www.opera.com Powered by Outblaze
