It's a stab in the dark ...

Good stab - I can make use of that. The following outputs "True False" on the buggy compilers (and "True True" on sane compilers): 
#include <stdio.h>

int main(void) {

   double nv = 2.0 / 3;
   float foo = 2.0 / 3;
   float truncated = (float)nv;

   if(foo == truncated) printf("True ");
   else printf("False ");

   if(foo == (float)nv) printf("True\n");
   else printf("False\n");

   return 0;
}

[download]
I can apply that method (used to obtain that "True") to PDL, which solves the problem I have asked about. Unfortunately, while it enables me to get the behaviour I want with my C demo scripts, it's still not producing the correct result with PDL - but this is such a fickle bug. I'll have to play around with it some more.

PS: This is relevant to the work I do ensuring Windows compatibility for my XS distros

#if defined _MSC_VER && _MSC_VER < 1400 then expect weirdness if you start comparing floats with doubles.

Thanks Marvin.

Cheers,
Rob

In reply to Re^2: [Win32, C, and way OT] C floats, doubles, and their equivalence by syphilis
in thread [Win32, C, and way OT] C floats, doubles, and their equivalence by syphilis

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.