> -----Original Message----- > From: Olle Raab [mailto:[EMAIL PROTECTED] > Sent: 23 September 2004 21:45 > To: [EMAIL PROTECTED] > Subject: Re: [fpc-pascal]Apple Mac pointer problem > > 04-09-23 23.09, skrev Stephen Downs följande: > > > -----Original Message----- > > From: Marcel Martin [mailto:[EMAIL PROTECTED] > > Sent: Thu 9/23/2004 9:18 PM > > To: [EMAIL PROTECTED] > > Cc: > > Subject: Re: [fpc-pascal]Apple Mac pointer problem > > > > Stephen Downs a écrit : > >> > >> I am porting a Mac CodeWarrior project to FreePascal and have hit a > >> compile problem with a pointer. In my original code I have a structure > >> defined along the lines of > >> > >> testData = record > >> testIndex : array [0..12] of integer; > >> end; > >> > >> testDataPointer = ^testData; > >> testDataHandle = ^testDataPointer; > >> > >> Within my main code I open a file and try to read it into my structure > >> > >> testDataHdl := testDataHandle(NewHandleClear(sizeof(testData))); > >> OSError := FSRead(fileRefNum, numberOfBytes, testDataHdl^) > >> > >> The FSRead line fails with error: 62: Incompatible type for arg no. 3: > >> Got "testDataPointer", expected "Ptr" - the third parameter for FSRead > is a > >> pointer. I presume this is because FreePascal uses typed pointers. > > The reason you get the error msg is that fpc supports UNIV as a dummy > keyword. Is it is accepted but doesn't do anything. > > Since the third param is declared UNIV you do not need any typecast in > Metrowerks, but you need to cast to Ptr in fpc (as Marcel suggests). > > From UI: > > FUNCTION FSRead(refNum: INTEGER; VAR count: LONGINT; buffPtr: UNIV Ptr): > OSErr; > > >> I > >> tried replacing testDataHdl^ by Ptr(testDataHdl)^ but that gives a > >> similar error - Got "ShortInt", expected "Ptr" > > The mac type Ptr is defined as usual in the UI, as a pointer to a signed > byte, hence the reference to ShortInt in the error msg, which is a signed > byte. > > >> Does anyone know how I can get around this? > > > >> This is very likely a stupid suggestion but have you tried this > >> > >> Ptr(testDataHdl^) > > > I had tried that and it compiles ok but when it runs, the FSRead > statement > > returns an error -36 which is an I/O error > > Are you shure nothing else is wrong ? > > If you read a binary file, alignment might not be the same. > > Actually FPC does not align arrays the same as trad mac compilers. >
Thanks for everyones input (Harold - it a Mac thing !!). I'm away for a couple of days now so won't be able to follow up until next week but I guess I need to read up on alignment of binary data. I assume from what you are saying is that Ptr(testDataHdl^) is the right way to do it in FreePascal but I need to check on how the data is read into the structure. > Olle > > > _______________________________________________ > fpc-pascal maillist - [EMAIL PROTECTED] > http://lists.freepascal.org/mailman/listinfo/fpc-pascal _______________________________________________ fpc-pascal maillist - [EMAIL PROTECTED] http://lists.freepascal.org/mailman/listinfo/fpc-pascal
