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Re^2: Determining the minimum representable increment/decrement possible? (Perl's scanf broken?)by BrowserUk (Patriarch) |
on Jun 17, 2016 at 13:41 UTC ( [id://1165975]=note: print w/replies, xml ) | Need Help?? |
Indeed. The previous post was done using 5.10.1; this is 5.22:
Of more importance is the source of the numbers that apparently cannot be represented by 64-bit floating point. At least in perl. They are produced & output by the C++ code I'm optimising. I originally thought that the C++ math was producing denormals and C++ was outputting them unnormalised, but that does not seem to be the case:
Even the latest perl seems just to be getting the conversion wrong!? Both numbers are representable with 64-bit Ieee754 numbers, so why Perl should silently convert one to the other is something of a mystery. Basically, Perl's (or the underlying CRT) input routine just seems to be broken. Update: The 5.22 perl I'm using is built with the same compiler and libraries as the C++ code; so this seems to be a PerlIO issue rather than a CRT issue. With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
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