Re^4: Windows / Linux puzzler

I think Veltro's point is likely irrelevant if both the Windows perl and Linux perl report the same value for $Config{nvsize}.

In at least some verisons of Perl, creating a float from a string is done by the underlying C library, and MS's library is known to not be as good as a gcc's.

Image showing the output varies by compiler

I didn't include nvsize in the screenshot, but both builds use IEEE double-precision floats.

Comment on Re^4: Windows / Linux puzzler

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Re^5: Windows / Linux puzzler by syphilis (Archbishop) on Mar 26, 2020 at 02:25 UTC
MS's library is known to not be as good as a gcc's All that the linked example demonstrates is that there's a discrepancy in the %.20g formatting - it says nothing about the ability to assign values correctly. If you compare the actual values by doing "%a" formatting on both the Linux and windows perls, you'll see that 0.1 is exactly the same double. Also, I believe the OP's activestate perl was built with (mingw port of) gcc. They stopped using Microsoft compilers a few years ago. ikegami's point is likely even more irrelevant than Veltro's. Cheers, Rob	[reply]
Re^6: Windows / Linux puzzler by ikegami (Patriarch) on Mar 26, 2020 at 21:36 UTC
If you compare the actual values by doing "%a" formatting on both the Linux and windows perls, you'll see that 0.1 is exactly the same double. Your are correct. `pack 'd'` shows this more definitely. `>perl -E"say sprintf '%vX', pack 'd>', $ARGV[0]" 0.1 3F.B9.99.99.99.99.99.9A` [download] `$ perl -E'say sprintf "%vX", pack "d>", $ARGV[0]', 0.1 3F.B9.99.99.99.99.99.9A` [download] I believe the OP's activestate perl was built with (mingw port of) gcc It definitely allows mingw to be used to compile modules, but I don't know if that's what used to build Perl itself. (Update: `perl -V` hints that it uses mingw) I beleive Strawberry Perl uses mingw, and I used Strawberry Perl in the test in the earlier post. If so, there are pertinent differences in the libraries between mingw and gcc.	[reply] [d/l] [select]
Re^7: Windows / Linux puzzler by syphilis (Archbishop) on Mar 26, 2020 at 23:33 UTC
there are pertinent differences in the libraries between mingw and gcc I think that with mingw, the MS runtime is still used by default for formatting of values. However, that is avoided (by building with -D__USE_MINGW_ANSI_STDIO) in recent versions of Strawberry Perl, beginning perl-5.26.0. (Look for "-D__USE_MINGW_ANSI_STDIO" in `perl -V:ccflags`) Of course, ActiveState don't build with -D__USE_MINGW_ANSI_STDIO. Cheers, Rob	[reply] [d/l]
Re^8: Windows / Linux puzzler by ikegami (Patriarch) on Mar 27, 2020 at 01:46 UTC
Re^9: Windows / Linux puzzler by syphilis (Archbishop) on Mar 27, 2020 at 07:11 UTC


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