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From: wmcb@ecsvax.UUCP (William C. Bauldry)
Newsgroups: comp.sys.mac
Subject: Re: How to launch an application
Message-ID: <2950@ecsvax.UUCP>
Date: Fri, 24-Apr-87 15:49:56 EST
Article-I.D.: ecsvax.2950
Posted: Fri Apr 24 15:49:56 1987
Date-Received: Sat, 25-Apr-87 20:39:00 EST
References: <1405@uwmacc.UUCP> <3326@linus.UUCP> <235@osupyr.UUCP>
Reply-To: wmcb@ecsvax.UUCP (Bill Bauldry)
Organization: UNC Educational Computing Service
Lines: 74
Keywords: launch

Here's a little routine to launch a program selected through the
standard file package. (Done with LightSpeed Pascal - great product!)

program launch;
const
   Launch=$A9F2; { * trap word * }

Var
   TopLeft: Point;
   PromptString : str255;
   FileFilter : ProcPtr;
   NumTypes : integer;
   TypeList : SFTypeList;
   DialogHook : ProcPtr;
   Reply : SFReply;

   myFile : Packed Record
      name: Ptr;
      buffers : integer;
    end;

   myFileHandle : Handle;

   registers = record
      a : array[0..4] of longint;
      d : array[0..7] of longint;
    end;

Procedure CleanUp;
 begin
  { * Clean up current application's mess before the Launch * }
 end;

begin { * Launch * }
   TopLeft.v := 75  { * where to put the dialog box * }
   TopLeft.h := 100;
   PromptString :=''; { * leftover from a previous system * }
   FileFilter := nil;
   NumTypes :=1;      { * we're just interested in applications * }
   TypeList[0] := 'APPL';
   DialogHook := nil;

   SFGetFile( TopLeft, PromptString, fileFilter, NumTypes, Typelist,
                     DialogHook, Reply);

   If (Reply.good:=true) then { * a file was selected to run * }
      begin
         CleanUp;

         myFile.name := @Reply.FName;
         myFileBuffers :=0;  { * 0 : launch with main screen & sound buffs * }
                             { * + :             main        & alternate   * }
                             { * - :             alt         & alt         * }

         registers.a[0] := longint(myFileHandle);

         Generic( Launch, registers );
      end; { * good launch * }

end. { * Launch * }

We havew to use the Generic call since this routine (Launch) expects
A0 to hold a pointer to the name followed by the code for the buffer
e. Launch is register not stack based.
i.e. Launch is a register, not stack, based routine.

Next week the Launch done in Assembler will appear.

-----------------------------------
Bill Bauldry
Dept. of Math Sci
Appalachian State U
Boone, NC 28608		(wmcb@ecsvax.UUCP)
allocations.