[Lazarus] Why Ln(0) and 1/0 does not trigger Exception?

[Xiangrong Fang]

X := 0; Ln(X) seems to generated an exception without need to adjust
exception mask. The reason I ask is that I get a strange crash while doing
my charting program, I just suspected the reason being an exception is
slipped through without being caught.

As this happened outside of IDE, I don't know the exact reason. I will do a
screenshot and ask again.

Thanks.

2013/3/5 Sven Barth <pascaldragon at googlemail.com>

> Am 04.03.2013 16:05, schrieb Xiangrong Fang:
>
>  As title.  My question is not just "it is a language construct", but
>> "WHY".  What's the benefit of doing so?
>>
> I already wrote this in the other thread: if you write "ln(0)" then the
> compiler will hardcode this as "NaN". I don't know what will happen with
> "ln(x)" with "x := 0" though. Maybe you'll need to set the exception mask
> correctly (see here: http://www.freepascal.org/**docs-html/rtl/math/**
> setexceptionmask.html<http://www.freepascal.org/docs-html/rtl/math/setexceptionmask.html>) to get an exception.
>
> Regards,
> Sven
>
>
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