Don wrote:
Walter Bright wrote:
Georg Wrede wrote:
Thanks, Don and Walter!!
I originally had this in the Digital Mars C compiler years and years
ago. I dropped it and moved away from it because not a single person
noticed or cared about it, plus the standard C spec failed to
distinguish between quiet and signaling nan's.
I'm glad to see it actually being of value, and it's a great idea.
I noticed there was a place in the backend where it was careful to
preserve the signallingness <g> of NaNs. So I thought, hmm, someone's
been here before.
Like a chicken that still has genes for dinosaur teeth lurking unactivated!
The key thing that makes it possible is that D initializes all floats to
NaN anyway, and since C doesn't do that, it's not as obviously
beneficial. By making NaN the default, you've made sure that practically
every D user knows about them. I bet that's not the case for C/C++. (I
even know numerical analyists who don't know much about them).
You can still know it's not the case for C/C++ given the crappy support
for nan in modern compilers.
