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Re: rand() function on Windows systems

by BrowserUk (Pope)
on Dec 30, 2016 at 20:32 UTC ( #1178680=note: print w/replies, xml ) Need Help??


in reply to rand() function on Windows systems

If you install Inline::C you can access the MS CRT rand() & srand() and wrap them in your own wrappers.

The following code produces 56 (which is the same as I get from Perl's built-ins for 5.10). You might try it on your system and see how it compares:

#! perl -slw use strict; use Inline C => Config => BUILD_NOISY => 1; use Inline C => <<'END_C', NAME => 'junk1_IC', CLEAN_AFTER_BUILD => 0 +; int osrand( SV *seed ) { srand( (unsigned int)SvIV( seed ) ); return 1; } double orand( SV *max ) { return (double)rand() / 32767.0 * SvNV( max ); } END_C osrand( 555 ); print int orand( 1000 );

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
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Re^2: rand() function on Windows systems
by bakiperl (Acolyte) on Dec 30, 2016 at 21:38 UTC

    Yes. That did the trick.

    Thank you BrowserUk

      Just for completeness, this pure perl version should also work:

      { my $seed; sub ppSrand{ $seed = int( $_[ 0 ] & 32767 ); } sub ppRand{ my $max = shift // 1; $seed = ( $seed * 214013 + 2531011 ); return ( ( $seed >> 16 ) & 32767 ) / 32768 * $max; ## Amend +ed per post below. } } ppSrand( 555 ); print int ppRand( 1000 );

      With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
      Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
      "Science is about questioning the status quo. Questioning authority". The enemy of (IT) success is complexity.
      In the absence of evidence, opinion is indistinguishable from prejudice.
        Thanks, BrowserUK. I have a low priority project which has been on hold for several years awaiting a solution to the problem described by the OP. Somehow, I overlooked the possibility of writing a generator. (The quality of the sequence is not an issue.) Your solution seems perfect!
        Bill
        Wow! This is even better. Thank you.

        That's very nice. I'm glad we have statistical analysts/mathematicians here.

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