1. Two nasty bugs in EC.EXE
I encountered a very nasty bug, and an incompatability
issue in EC.EXE.
1. I tried to translate a program wich uses NEIL.E
into C for DJGPP. EC.EXE tells me that built-in
pixel() is being redfinied, while inte interpreter
runs the program without errors. I did not include
graphics.e nor image.e, just neil.e.
2. I translate Jiri's flowers.ex program wich comes
with his map.e library. Once compiled and linked, I
try to run it, yet get a very nasty dos extender crash
immediatly after the delay. Yet the interpreter runs
flowers.ex without any problems.
Robert, please fix these bugs, especially that last
one, for it's very, very nasty.
Mike The Spike
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2. Re: Two nasty bugs in EC.EXE
Mike The Spike writes:
> 1. I tried to translate a program wich uses NEIL.E
> into C for DJGPP. EC.EXE tells me that built-in
> pixel() is being redfinied, while inte interpreter
> runs the program without errors. I did not include
> graphics.e nor image.e, just neil.e.
It's true that pixel() is redefined in neil.e, and in the absence
of "without warning" you will see a warning message about it.
Don't confuse warning messages with error messages.
ec will produce warnings, just like the interpreter.
It doesn't mean you can't run your .exe.
> 2. I translate Jiri's flowers.ex program wich comes
> with his map.e library. Once compiled and linked, I
> try to run it, yet get a very nasty dos extender crash
> immediatly after the delay. Yet the interpreter runs
> flowers.ex without any problems.
> That second bug in EC.EXE I just posted turned out to
> be a missing bitmap file in the directory wich
> flowers.ex needed to run.
> This is still a bug, since I expected a runtime error
> message, not a crash.
No, it's not a bug.
The crash occurs because Jiri's code does not
allow for the possibility that read_bitmap() will
return an integer error code when it can't find the
bmp file. So you have something like this:
x=read_bitmap("3f.bmp")
pal=x[1]/4
Here, Jiri is assuming that read_bitmap() will never fail.
He is assuming that a sequence will always be returned.
When 3f.bmp does not exist, x is set to error code 1,
x[1] therefore makes no sense. The interpreter checks
for stuff like this and issues an error report. The translated
C code does not check, and a crash occurs.
The translator assumes that you have debugged your
program. In the interest of maximizing speed
it eliminates most checks. There are still a few checks
in the runtime routines that are shared between the
translator and the interpreter, so you will occasionally
get a ex.err file, but for the most part if you make a stupid
error "all bets are off" and an ugly crash is likely to occur.
(Just like with hand-written C programs.)
When your .exe crashes, you should run the program
again using the interpreter to find your mistake.
Regards,
Rob Craig
Rapid Deployment Software
http://www.RapidEuphoria.com
