Re: [boost] [endian] Some suggestions

Subject: Re: [boost] [endian] Some suggestions
From: Gavin Lambert (gavinl_at_[hidden])
Date: 2016-04-10 19:47:08

On 11/04/2016 04:10, Bjorn Reese wrote:
> Another problem related to the above is that the NaN payload is
> implementation-defined, so even if the exact bit-pattern is preserved,
> programs compiled with different compilers may interpret the payload
> differently.

While that's true, surely any compiler/library should treat any NaN bit 
pattern as returning true from isnan() and friends, even if it is not 
bit-identical to the NaN that the compiler/library would generate itself.

Using it in a further calculation might result in a different NaN bit 
pattern, but that's expected behaviour anyway.

So at least in theory it should work unless there are bugs in the 
compiler/library or in the application (eg. it is not an error if 
<external NaN> != <internal NaN>; it's an app bug if it makes an 
equality assumption -- for that matter equality can't even be assumed 
between internal NaNs).