According to Michael Howard of Microsoft, you can obtain true random numbers under Windows XP without having to deal with their full-blown CryptAPI.

Using XS, I have written a function to return an array ref of random ints using the referenced API. 

#include <windows.h>

SV *
random(count)
    int count
  CODE:
    /* REFERENCE:
        http://blogs.msdn.com/michael_howard/archive/2005/01/14/353379
+.aspx */

    /* Open the library */
    HMODULE lib = LoadLibrary("ADVAPI32.DLL");
    if (! lib) {
        Perl_croak(aTHX_ "ADVAPI32.DLL not found");
    }

    /* 'Extract' the function */
    BOOLEAN (APIENTRY *RtlGenRandom)(void*, ULONG) =
        (BOOLEAN (APIENTRY *)(void*,ULONG))GetProcAddress(lib,
                                                          "SystemFunct
+ion036");
    if (! RtlGenRandom) {
        FreeLibrary(lib);
        Perl_croak(aTHX_ "RtlGenRandom() not found in ADVAPI32.dll");
    }

    /* Set up a temporary buffer */
    U32 *buff = (U32 *)malloc(count * sizeof(U32));

    /* Get the random data */
    if (! RtlGenRandom(buff, (ULONG)(count * sizeof(U32)))) {
        free(buff);
        FreeLibrary(lib);
        Perl_croak(aTHX_ "RtlGenRandom() failed");
    }

    /* Copy the data to a Perl array */
    AV *array = newAV();
    int ii;
    for (ii=0; ii<count; ii++) {
        av_push(array, newSVuv(buff[ii]));
    }

    /* Cleanup */
    free(buff);
    FreeLibrary(lib);

    /* Return an array ref */
    RETVAL = newRV((SV *)array);
  OUTPUT:
    RETVAL

[download]
I would like to have a Perl version of this that uses Win32::API. The problem is that I use Perl under Cygwin, and Win32::API won't compile under Cygwin. Would someone be so good as to assist in translating this for me? Thank you.

(Yes, I know that /dev/random is available under Cygwin. I want to provide the code to others that are using Perl on PCs, but are not using Cygwin.)


Remember: There's always one more bug.

In reply to Random Numbers under XP: Translating XS to Win32::API by jdhedden

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