Hi,
Using a recent installation of Cygwin (which comes with a "use64bitint" version of perl 5.8.7) I find the following: 
Rob@desktop ~/pscrpt
$ cat try.pl

use warnings;

$x = 2 ** 54 + 123; # 18014398509482107
$y = 2 ** 54 + 125; # 18014398509482109

if($x + 2 == $y) {print "fine\n"}
else {print "crap\n"}

if($x == $y) {print "crap\n"}
else {print "fine\n"}


Rob@desktop ~/pscrpt
$ perl try.pl
crap
crap

[download]
Now that output doesn't quite coincide with what I expected from a perl that claims to have been built with "use64bitint".

Is there something else I'm overlooking ? ... or am I just being plain unreasonable ? The full output of 'perl -V' appears below my sig.

Cheers,
Rob 
$ perl -V
Summary of my perl5 (revision 5 version 8 subversion 7) configuration:
  Platform:
    osname=cygwin, osvers=1.5.18(0.13242), archname=cygwin-thread-mult
+i-64int
    uname='cygwin_nt-5.1 inspiron 1.5.18(0.13242) 2005-07-02 20:30 i68
+6 unknown
unknown cygwin '
    config_args='-de -Dmksymlinks -Duse64bitint -Dusethreads -Uusemyma
+lloc -Doptimize=-O3 -Dman3ext=3pm -Dusesitecustomize'
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=define use5005threads=undef useithreads=define usemulti
+plicity=define
    useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
    use64bitint=define use64bitall=undef uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='gcc', ccflags ='-DPERL_USE_SAFE_PUTENV -fno-strict-aliasing -p
+ipe -I/usr/local/include',
    optimize='-O3',
    cppflags='-DPERL_USE_SAFE_PUTENV -fno-strict-aliasing -pipe -I/usr
+/local/inc
lude'
    ccversion='', gccversion='3.4.4 (cygming special) (gdc 0.12, using
+ dmd 0.125)', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=12345678
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=1
+2
    ivtype='long long', ivsize=8, nvtype='double', nvsize=8, Off_t='of
+f_t', lseeksize=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='ld2', ldflags =' -s -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib
    libs=-lgdbm -ldb -lcrypt -lgdbm_compat
    perllibs=-lcrypt -lgdbm_compat
    libc=/usr/lib/libc.a, so=dll, useshrplib=true, libperl=libperl.a
    gnulibc_version=''
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=dll, d_dlsymun=undef, ccdlflags=' -s'
    cccdlflags=' ', lddlflags=' -s -L/usr/local/lib'


Characteristics of this binary (from libperl):
  Compile-time options: MULTIPLICITY USE_ITHREADS USE_64_BIT_INT
                        USE_LARGE_FILES USE_SITECUSTOMIZE
                        PERL_IMPLICIT_CONTEXT
  Locally applied patches:
        SPRINTF0 - fixes for sprintf formatting issues - CVE-2005-3962
  Built under cygwin
  Compiled at Dec 30 2005 02:44:25
  %ENV:
    CYGWIN=""
  @INC:
    /usr/lib/perl5/5.8/cygwin
    /usr/lib/perl5/5.8
    /usr/lib/perl5/site_perl/5.8/cygwin
    /usr/lib/perl5/site_perl/5.8
    /usr/lib/perl5/site_perl/5.8/cygwin
    /usr/lib/perl5/site_perl/5.8
    /usr/lib/perl5/vendor_perl/5.8/cygwin
    /usr/lib/perl5/vendor_perl/5.8
    /usr/lib/perl5/vendor_perl/5.8/cygwin
    /usr/lib/perl5/vendor_perl/5.8
    .

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In reply to -Duse64bitint and (Cygwin) perl 5.8.7 by syphilis

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