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Q162084: PRB: Non-Standard RETURN TO MASTER Behavior After LOCATE Error

Article: Q162084
Product(s): Microsoft FoxPro
Version(s): MACINTOSH:3.0b; WINDOWS:3.0,3.0b,5.0
Operating System(s): 
Keyword(s): 
Last Modified: 04-FEB-2000

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b, 5.0 
- Microsoft Visual FoxPro for Macintosh, version 3.0b 
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SYMPTOMS
========

In an error-handling routine of a sub-program, a RETURN TO MASTER command
returns processing to the highest level running program.

An error caused by a faulty LOCATE FOR command does not result in a successful
RETURN TO MASTER until after first returning to the command immediately
following the line that caused the error.

STATUS
======

Microsoft is researching this behavior and will post new information here in the
Microsoft Knowledge Base as it becomes available.

MORE INFORMATION
================

Steps to Reproduce Behavior
---------------------------

Copy the following two programs, and paste them into appropriately named program
(.prg) files:

1. Copy the following into a program named ReturnFail:

     ** Returnfail.prg - demonstrates failure of
     ** RETURN TO MASTER in a class error method
     DEFINE CLASS returntest AS custom
        PROCEDURE init
           CLEAR
           USE HOME()+"samples\data\customer"
           ERROR 12, "MyError"
           *LOCATE FOR CustHeight="Steve" && No such column in table
           =MESSAGEBOX("It didn't return to master")
        ENDPROC

        PROCEDURE error
           LPARAMTERS  nError, cMethod, nLine
           =MESSAGEBOX("The error is " + STR(nError,2,0) + ;
               " in " + cMethod +" method.")
           RETURN TO MASTER
        ENDPROC
     ENDDEFINE

2. Copy the following into a program named TryFail:

     ** Tryfail.prg - program to test the failure of
     ** RETURN TO MASTER in a class where the error is
     ** caused by a LOCATE FOR fault.
     CLEAR
     CLOSE ALL
     SET PROCEDURE TO returnfail
     oRef = CREATEOBJECT("returntest")
     =MESSAGEBOX("It did return to master")

3. Run TryFail with the command "Do tryfail" (without the quotation marks).
  Observe that the only message is "It did return to master."

4. Edit the program "ReturnFail" by issuing the following command:

  " MODIFY COMMAND returnfail " (without the quotation marks)

  Find the following two lines of code:

        ERROR 12, "MyError"
        *LOCATE FOR CustHeight="Steve" && No such column in table

  Remove the asterisk from the second line, and place an asterisk to the left of
  the first so that the lines look like:

        *ERROR 12, "MyError"
        LOCATE FOR CustHeight="Steve" && No such column in table

  Save that program.

5. Run tryfail again and observe the second and third messages.

An error caused by the ERROR command causes an error, and the error method
successfully issues a RETURN TO MASTER command, which successfully returns to
the highest level running program.

An error caused by a faulty LOCATE FOR command does not result in a successful
RETURN TO MASTER until after first returning to the command immediately
following the line that caused the error.

Additional query words: vfoxwin kbdsd

======================================================================
Keywords          :  
Technology        : kbHWMAC kbOSMAC kbVFPsearch kbAudDeveloper kbVFP300bMac kbVFP300 kbVFP300b kbVFP500
Version           : MACINTOSH:3.0b; WINDOWS:3.0,3.0b,5.0

=============================================================================

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