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From: aries@rhi.hi.is (Reynir Hugason)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Breaking out of a series of routines
Message-ID: <1838@krafla.rhi.hi.is>
Date: 10 Jul 90 20:20:53 GMT
References: <25526@cs.yale.edu> <5252@plains.UUCP> <2745.2699a0d0@cc.helsinki.fi>
Organization: University of Iceland
Lines: 54

>On an error condition I wish to immediately stop processing a large file
>and break out of about 10 routines that have been calling each other and
>return to my main event loop. Is there any way to do this without
>passing and error flag to each of the calling routines?

Here is an examplery clean way of doing it, assuming you're using Pascal 8)

UNIT FileReader;

INTERFACE
   USES ...

   PROCEDURE ReadFile;
   FUNCTION  Status: INTEGER;

   ... and so on ...

IMPLEMENTATION

   VAR
      errFlag: INTEGER;

   PROCEDURE ReadFile;

      PROCEDURE CheckError;
         BEGIN
            IF (errFlag <> noErr) THEN
               BEGIN

                  { Clean-up now }

                  EXIT(ReadFile);
               END;
         END;

         { Here come your procedures for reading the file }

      BEGIN

         { Initiate sequence }

      END;

   FUNCTION  Status: INTEGER;
      BEGIN
         Status:=errFlag;
      END;
END.

---

Well that's it, now try to do that in C !!! 8)

Mimir (aries@rhi.hi.is) - Aries Software, Inc.