I don't know that that is a reasonable expectation

Yes, I don't know if it's reasonable, either - but it does appear to be reliable except when a pre-VC8 MS Compiler is being used.

In general, exact equalities on doubles and floats is not a good idea. I'm a little surprised that PDL code is assuming that it is

No - that assumption is not being made ... well, not explicitly, anyway. The exact problem I'm looking at is not all that complex:

Basically, if you have a piddle (array) of values, you should be able to call setvaltobad(123), and every occurrence of 123 in that piddle will be changed to 'BAD'. So, if we have a piddle of floats [1/3, 2/3, 1, 4/3] and we call setvaltobad(2/3), then that piddle should become [1/3, BAD, 1, 4/3]. And that's exactly what happens ... unless we're using one of those older Microsoft Comnpilers (in which case the piddle remains unchanged).
Now, part of the problem is probably that setvaltobad(2/3) passes a double (NV). But that's not a problem with any compiler other than the ones I've already specified (afaik).

It's the sort of thing that probably won't ever affect anyone ... but there's a test for this in the current test suite, that test fails when PDL is built with one of the older Microsoft Compilers, and it would be nice to fix that failure without having to go to too much trouble.

(Unfortunately, it has already become "too much trouble" :-)

Cheers,
Rob

In reply to Re^4: [Win32, C, and way OT] C floats, doubles, and their equivalence by syphilis
in thread [Win32, C, and way OT] C floats, doubles, and their equivalence by syphilis

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