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Re: Built-in testing for signaling nan?
- From: FX <fxcoudert at gmail dot com>
- To: Ian Lance Taylor <iant at google dot com>
- Cc: GCC Development <gcc at gcc dot gnu dot org>, gfortran <fortran at gcc dot gnu dot org>
- Date: Thu, 7 Nov 2013 08:36:39 +0100
- Subject: Re: Built-in testing for signaling nan?
- Authentication-results: sourceware.org; auth=none
- References: <603BA745-9844-45FE-A830-9F6F6EEC82B9 at gmail dot com> <CAKOQZ8xu-BQgKba9vBg7VOZ-x5yStE9w1psTcMTQketo81MF=w at mail dot gmail dot com>
> Given how murky signaling NaNs are in practice, I think it's worth
> asking: why do you want to know?
Because I am writing an implementation of the IEEE support modules in GNU Fortran, which are part of the Fortran 2003 standard. And the standard provides for a procedure (IEEE_CLASS) to distinguish between IEEE_SIGNALING_NAN and IEEE_QUIET_NAN. It doesn’t explicitly state that supporting sNaN is required, so I can also just not return it.
FX