Thanks so much Robert,

That cleared a lot of the fog. Now I just have to study this to make
it jell.

BTW you have just supplied me with a good set of REMs for my app. :-)

Bruce Gottshall
 
On Mon Sep 6 09:01:40 2004 Robert Covington wrote:

>On Monday, September 6, 2004, at 08:26   AM, BrucesFB3@... wrote:

>> Hello All,
>>
>> Given the code below:
>>
>> I understand this has something to do with opening files by
>> double clicking icons in the Finder.
>>
>> I have been able to use the functions successfully. Everything
>> works.
>>
>> My problem is that I don't know why it works. Obviously,
>> FN FBWDToFSSpec() is checking for a particular type of error.
>> What kind of error? What is the trigger?

>I believe that it is checking that the file/folder exists in this 
>case...if it does, no error will occur.
>
>Often times one has to make an FSSpec for a file that doesn't exist 
>yet, so you'll get a -43 File Not Found error returned. In this case it 
>seems that it wants to verify that it does exist already, so if there's 
>noErr, then all is fine.
>
>
>> Also in FN FBWDToFSSpec(), what are the purposes of
>> FN FBWDToPBWD( pb ) and FN PBGetCatInfoSync( pb).
>> What is the CInfoPBRec?

>> FN FBWDToPBWD( pb )

>That makes a "classic" type of Param block situation work in Carbon, 
>the main difference being that in classic, a vRefnum is often a Working 
>Directory Reference number (folder number basically, an open one that 
>the system gives you)... and not a real volume reference number.
>
>In Carbon however, you need to use true vRefNums, which in OS X are 
>numbered -100,-200, -300 etc...for the volumes mounted. And also the 
>Directory ID's need to be sync'ed up or filled in too. FB does a lot of 
>this transparently using the FN FBWDToPBWD( pb ) convention, 
>automatically refinancing a WD into a VRefnum and doing any DirID work 
>too (I believe)
>
>You only need that in Carbon. It insures that the PB calls will return 
>valid results in carbon so you don't go writing to the North Pole when 
>you want the South, or just get stuck at the equator with no results.

>>
>> What is the meaning of the syntax, AS .Str63? (period before Str63).
>
>That means Pointer to String 63. Say you have   dim 63 myText$
>You can pass that as @myText$[1]    or often simply, @myText$
>Where that is going to will have it incoming as a string pointer.
>Things like DrawText will want the former. Byte [0] is the length byte. 
>But FB will convert a string to a pointer as you go along, often don't 
>need to worry about it, as you can see in that code..only gFile$ is 
>passed in fn readFile$ , not @gFile$.
>
>Might be off on a couple, but hopefully I am not filling your head with 
>gunk. :)
>
>rc
>
>> Bruce Gottshall
>>
>> ====================
>> In the file handling code
>> ====================
>>
>> Clear Local Mode
>> Local Fn FBWDToFSSpec(@namePtr As .Str63, vRefNum As Int,fSpec As 
>> .FSSpec)
>> Dim err As OSErr
>> Dim pb    As CInfoPBRec
>> '~'<
>> pb.ioNamePtr = namePtr
>> pb.ioVRefNum = vRefNum
>> #If CarbonLib
>> Fn FBWDToPBWD( pb )
>> #Endif
>> err = Fn PBGetCatInfoSync( pb )
>> If err != _noErr Then Exit Fn
>> fSpec.name      =    namePtr.nil$
>> fSpec.vRefNum =    pb.ioVRefNum
>> fSpec.parID     =    pb.ioFlParID
>> End Fn = err
>> '~'4
>> '==============================
>> clear local
>> dim theErr as OSErr
>> dim AppFolderRef as long
>> '~'1
>> local fn readFile$
>> AppFolderRef = system(_aplVol)
>> theErr=fn FBMakeFSSpec(AppFolderRef,0,"",dataFileSpec)
>> '-------------------------------------------------
>> long if fn FBMakeFSSpec(AppFolderRef,0,"",dataFileSpec) = _noErr
>> '-------------------------------------------------
>> long if gFound
>> xelse
>> gFile$ = FILES$ (_FSSpecOpen,"ZDAT","Open which?...", dataFileSpec)
>> gFound=_ztrue
>> end if
>> '-------------------------------------------------
>> long if len(gFile$)                     // if not CANCELled
>> long if Fn FBWDToFSSpec( gFile$, gVolRefNum, dataFileSpec ) = _noErr or
>> gFound
>> open "I",#1,@dataFileSpec
>> '------------------------------------------------
>> FOR j=0 TO gNI
>> READ #1, gDate$(J);8, gItem$(J);44, gComm$(J);44
>> READ #1, gChNum$(J);12, gAmt$(J);12
>> NEXT j
>> '------------------------------------------------
>> CLOSE #1
>> end if
>> end if
>> end if
>> end fn = gFile$
>>

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