[fpc-pascal] math with infinity and NaN

[James Richters]

Is there a way to prevent getting the runtime error?

James 
-----Original Message-----
From: fpc-pascal [mailto:fpc-pascal-bounces at lists.freepascal.org] On Behalf Of Florian Klämpfl
Sent: Wednesday, June 20, 2018 4:59 PM
To: fpc-pascal at lists.freepascal.org
Subject: Re: [fpc-pascal] math with infinity and NaN

Am 19.06.2018 um 23:50 schrieb James Richters:
> I’ve been updating my old programs to use the MATH unit in freepascal 
> and while testing things I came across a runtime error 217  Invalid 
> floating point operation.  Here is my test program
> 
> Uses math;
> 
> var
> 
>     variable1:double;
> 
>     variable2:double;
> 
> Begin
> 
> variable1:= Infinity;
> 
> variable2:= -1*Infinity;
> 
> Writeln(variable1,' ',Variable2,' ',Variable1+Variable2);
> 
> End.
> 
> My output is:
> 
> Running "i:\programming\test\testmath.exe "
> 
> An unhandled exception occurred at $004015F6:
> 
> EInvalidOp: Invalid floating point operation
> 
>    $004015F6  main,  line 8 of i:/programming/test/testmath.pas
> 
>                      +Inf                     -Inf
> 
> According to the link here: https://en.wikipedia.org/wiki/NaN
> 
> NaN should be produced:

No. The invalid operation is not masked by default. If you do so, FPC just write Nan.
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