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Q38493: CodeView Problem Stepping into BASIC GOSUB Compiled /X or /D

Article: Q38493
Product(s): See article
Version(s): 4.50
Operating System(s): MS-DOS
Keyword(s): ENDUSER | S_CodeView B_BasicCom buglist4.00 buglist4.00b buglist4.50 | mspl13_basic
Last Modified: 20-SEP-1990

If you compile the program below with BC /X or /D in addition to the
/Zi option (and then LINK with /CO) for Microsoft CodeView
compatibility, the GOSUB subroutine cannot be "stepped into" in
CodeView (using the F8 key in CV.EXE). The CodeView stepping-in
process works correctly if the program is compiled without /X and
without /D. The compiler switch /X is needed to do error trapping
using ON ERROR with RESUME statements.

To work around this limitation, do the following:

1. When the GOSUB is encountered, switch the View option to "Mixed"
   mode and step through lines in "Mixed" mode until the subroutine
   is reached, then switch back to "BASIC" mode.

2. When the RETURN statement is reached, go back into "Mixed" mode
   until you are back to the line after the GOSUB.

Microsoft has confirmed this to be a problem in Microsoft QuickBASIC
versions 4.00, 4.00b, and 4.50; in Microsoft BASIC Compiler versions
6.00 and 6.00b for MS-DOS and MS OS/2 (buglist6.00, buglist6.00b); and
in Microsoft BASIC Professional Development System (PDS) versions 7.00
and 7.10 for MS-DOS and MS OS/2 (buglist7.00, buglist7.10). We are
researching this problem and will post new information here as it
becomes available.

Code Example
------------

   CLS
   PRINT "Point 1"
   GOSUB 100
   PRINT "Point 3"
   END

   REM * Subroutine *
   100 PRINT "Point 2"
   200 RETURN

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