Re^4: Number too big to fit in integer

I get the same with 5.36.0 as I did with 5.26.1.

Oh, I see. You were adding powers of 2 to the original value of 2**64.
I get the same as you when I run the code you provided.

I was incrementing by one:

D:\>perl -MMath::BigInt -wle "$x = Math::BigInt->new(~0); $x++; while(
+\"$x\" == ~0){$x++}; print $x;"
18446744073709553665
[download]

Of course, this particular perl configuration sees 18446744073709553665 and 18446744073709554600 as the same value, anyway:

D:\>perl -le "print 'ok' if 18446744073709553665 == 184467440737095546
+00;"
ok
[download]

However, that your 5.26.1 regards 18446744073709554600 and 18446744073709554599 as different values is a bug in 5.26.1. (I see the same bug in my Windows build of 5.26.0.)
I believe that perl should regard those two values as equivalent for all IV and NV configurations.

D:\>perl -wle "print 'ok' if 18446744073709554600 == 18446744073709554
+599;"
ok
[download]

For me, that fails to output 'ok' on 5.26.0. (If 5.26.0 has been built with -Duselongdouble, then 5.26.0 does get it right and outputs 'ok'.)

Cheers,
Rob

Comment on Re^4: Number too big to fit in integer Select or Download Code

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Re^5: Number too big to fit in integer by hv (Prior) on Jan 01, 2023 at 04:27 UTC
Ok, there has been a change somewhere along the line: if I compare "n more than ~0" against "~0" for integer n, up to 5.28 it first compares different for n = 2985 (ie with 18446744073709554600); with 5.30 and later it first compares different for n = 2050 (ie with 18446744073709553665): `% /opt/v5.28.1/bin/perl -MMath::BigInt -we '$z0 = Math::BigInt->new(~0 +); for (1..4096) { $z1 = $z0 + $_; $n1 = "$z1"; die $_ if $n1 != ~0 } +' 2985 at -e line 1. % /opt/v5.30.0-d/bin/perl -MMath::BigInt -we '$z0 = Math::BigInt->new( +~0); for (1..4096) { $z1 = $z0 + $_; $n1 = "$z1"; die $_ if $n1 != ~0 + }' 2050 at -e line 1. %` [download] (From the naming I know that's a v5.30.0 built with debugging, but that shouldn't make a difference here.)	[reply] [d/l]
Re^6: Number too big to fit in integer by syphilis (Archbishop) on Jan 01, 2023 at 09:40 UTC
Ok, there has been a change somewhere along the line: Yes - beginning with perl-5.30.0, perl uses C's strtod() to assign values, instead of its own (buggy) atof routine that it had previously been using. That fixed many errors in assignment - eg https://github.com/Perl/perl5/issues/8730, which had been reported in Jan 2007. Cheers, Rob	[reply]


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