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I think that checking whether the UV arg == (UV)((NV)arg) is a splendid idea

Unfortunately this check fails for some UV values with less recent Microsoft Compilers - eg Visual Studio 2010 and earlier.
No problems with Visual Studio 2017 and Visual Studio 2019.
I suspect that Visual Studio 2015 is the oldest Microsoft Compiler that doesn't suffer from this problem, but I haven't confirmed that.

This particular issue looks like another manifestation of the problem that sent me down this path in the first place.
Here's the demo I ran:
use strict; use warnings; use Inline C => Config => BUILD_NOISY => 1; use Inline C => <<'EOC'; int uv_fits_double1( UV arg ) { if(arg == (UV)((NV)arg)) return 1; return 0; } int uv_fits_double2(UV arg) { while(!(arg & 1)) arg >>= 1; if(arg < 9007199254740993) return 1; return 0; } EOC my $ls = 63; my @in = ( 18446744073709549568, 18446744073709139968); for(@in) { print "$_: ", uv_fits_double1($_),uv_fits_double2($_), "\n" +; } __END__ With Windows Server 2003 SP1 Platform SDK, this outputs: 18446744073709549568: 01 18446744073709139968: 01 Base 2 representations of the 2 Uvs is (resp): 1111111111111111111111111111111111111111111111111111100000000000 1111111111111111111111111111111111111111111110011011100000000000 showing that both are exactly representable by a double.


In reply to Re^3: Detecting whether UV fits into an NV by syphilis
in thread Detecting whether UV fits into an NV by syphilis

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