divide by zero - nasty crash

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slenkar

(Posted 2009) [#1]

Local the_int=0

Local x=1/the_int

Print x

there is no warning message when running this program,
it took me a few hours to track down why my game was crashing on windows
due to a mistake I was dividing by zero.
Is this just something we have to look out for? or is it a bug that it doesnt highlight the offending line and provide an error message instead of just crashing?

GIB3D

(Posted 2009) [#2]

Usually I just use a floating point number and it doesn't give me any error.

Local the_int=0

Local x=1.0/the_int

Print x

But of course I use Blitz3D so I don't know if it works with BlitzMax.

r	(Posted 2009) [#3]

@ GIB3D = on blitzmax no errors but the result is :-2147483648

_Skully

(Posted 2009) [#4]

Always ensure you don't get a divide by zero... always

Brucey

(Posted 2009) [#5]

Interesting, on my Mac I get the crash console reporting :

Exception Type:  EXC_ARITHMETIC (SIGFPE)
Exception Codes: EXC_I386_DIV (divide by zero)
Crashed Thread:  0  Dispatch queue: com.apple.main-thread

I'm pretty sure that BlitzMax used to throw a runtime exception in debug mode rather than crashing out like this.

GfK	(Posted 2009) [#6]

Always ensure you don't get a divide by zero... always

I'm fairly confident he didn't put the error in his code on purpose - he's simply saying that the lack of a runtime error made it nigh on impossible to track down.

My line intersection code (code arcs) had a divide by zero problem at first but it didn't crash - it just printed an unexpected result. I wonder if its OS specific? I wrote it under Windows 7 I think.