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in reply to How do I use "Long Doubles" in perl?

d_longdbl merely means that Configure probed the C library on the build system and found that the ldexpl() function is present.

uselongdouble means that your perl was configured and built with Configure -Duselongdouble so that the floating point variables perl uses are long double.

Dave.

  • Comment on Re: How do I use "Long Doubles" in perl?

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Re^2: How do I use "Long Doubles" in perl?
by cnd (Acolyte) on May 20, 2018 at 06:38 UTC

    Ahh - interesting. Thanks! So d_longdbl is more-or-less a pointless indicator, since the missing "uselongdouble" indicates that even though it existed, it was not incorporated at compile time.

    Shame. Might have been nice to use - the uncertainty of major breakage dampens my desire to do the rebuild unfortunately... it's on an important business system...

      the uncertainty of major breakage dampens my desire to do the rebuild unfortunately

      I think that such caution is unwarranted.
      If you do the rebuild with -Duselongdouble and the build still passes its tests, then there is no major breakage.
      As regards minor breakages (ie errors not picked up by the test suite) - they are just as likely to be present in the "double" builds as in the "long double" builds.

      Cheers,
      Rob