Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!ucsd!hub!mango!erbo
From: erbo@mango.ucsb.edu (Eric J. Bowersox)
Newsgroups: comp.databases
Subject: Re: dBASE IV -- Trials and Tribulations
Summary: the plot thickens....
Keywords: bugs
Message-ID: <2095@hub.UUCP>
Date: 20 Jul 89 00:00:38 GMT
References: <2071@hub.UUCP> <167@dbase.UUCP>
Sender: news@hub.UUCP
Reply-To: erbo@mango.UUCP (Eric J. Bowersox)
Organization: UC Santa Barbara, Campus Club for Computer People (CCCP)
Lines: 113

In article <167@dbase.UUCP> awd@dbase.UUCP (Alastair Dallas) writes:
:In article <2071@hub.UUCP>, erbo@lime.ucsb.edu (Eric J. Bowersox) writes:
:> BUG #1:	The Case of the Missing Procedure  (or: Son of Line Eater? :-) )
:I couldn't get this to fail.  I created a 150-line prg containing 14 simple,
:but not empty procedures.  The main proc just called the others, and the last
:one was never ignored.

After seeing this message for the first time, I ran back to my machine at
work (a true-blue IBM PC-XT with 20Mb hard disk -- slow! :-( ) and tried
to duplicate the problem.  Here's what I came up with:

*** DBFail.prg
*** A failing test case that demonstrates the procedure bug.
***************************************
***
*** Set up error logging.
***
set talk off
set space off
set alternate to "dbfail.run"
set alternate on
on error ? "Error ",error()," at ",program(),"-",lineno(),": ",message()
***
*** Test procedure calls.
***
? "Now starting the procedure call test..."
do test1
do test2
do test3
do test4
do test5
do test6
do test7
do test8
do test9
do test10
***
*** Finish up.
***
? "End of DBFAIL.PRG"
set alternate off
close alternate
return

*** The test procedures, ten in number.

procedure test1
  ? "Procedure TEST1 called!"
return

[The remaining procedures omitted for brevity, but they're just like the first
one]

*** EOF: DBFail.prg

Well, after compiling this with "compile dbfail" and getting no errors (I
know you don't need to do that, since dBASE will do it for you, but I just
wanted to make sure :-) ), I ran the program and got the following results
in DBFAIL.RUN:

Now starting the procedure call test...
Procedure TEST1 called!
Procedure TEST2 called!
Procedure TEST3 called!
Procedure TEST4 called!
Procedure TEST5 called!
Procedure TEST6 called!
Procedure TEST7 called!
Procedure TEST8 called!
Procedure TEST9 called!
Error          1 at DBFAIL-        25: File does not exist
End of DBFAIL.PRG

A-ha!  You think!  Well, I thought of something else, and rebooted my machine,
selecting "local boot" instead of "network boot." (Oops!  Forgot to mention,
my machine is a workstation on a LAN, but dBASE IV was installed single-user
on my own hard disk.)  Cranking up dBASE IV, recompiling DBFAIL.PRG, and
running it again produced the following:

Now starting the procedure call test...
Procedure TEST1 called!
Procedure TEST2 called!
Procedure TEST3 called!
Procedure TEST4 called!
Procedure TEST5 called!
Procedure TEST6 called!
Procedure TEST7 called!
Procedure TEST8 called!
Procedure TEST9 called!
Procedure TEST10 called!
End of DBFAIL.PRG

Checking both .DBO files out with LIST (the program LIST.COM, not dBASE's
LIST command :-) ) in hex dump mode revealed, sure enough, the one compiled
with the LAN on was missing the last entry in its "jump table" (for procedure
TEST10), but the one compiled with the machine booted locally had it in its
correct place.  Logically, though, both files should have been identical
whether the LAN was present or not.  I am afraid I am totally at a loss to
explain this, but I have a sneaking suspicion that Alastair is probably
right.  (sigh)

:Thanks for presenting such clear cases.  I think the people on comp.databases
:who don't hit 'N' when the subject line says 'dBASE' appreciate hearing 
:about any bugs or unexpected features (:-).

You're welcome.  Actually, I tune in _just_ to find out anything new I can
about dBASE...as my paycheck depends on it, this is understandable :-).
I think it's probably worth it in the end, though.

| Disclaimer:  This posting is definitive.  Reality may have got it wrong.    |
| * Eric J. Bowersox (ERBO) *  LIVE! from Isla Vista, California!             |
| erbo@cornu.ucsb.edu ...!{ucbvax,ucsd}!ucsbcsl!cornu!erbo                    |
| If wishes were DRAMs, I don't think we would worry about the Japanese. -me  |