Just like some numbers are periodic in decimal (e.g. 1/3), some numbers are periodic in binary (e.g. 6/10). They cannot be represented exactly using a float since that would require infinite storage.

You shouldn't check if two floats are equal. You should check if two floats are sufficiently identical. 

my $calc = (((63 - -90)/.6) * 601) + (360 /.6);

ok( abs( $calc - 153855 ) < 0.000000001 )
    or diag("Expected 153855. Got $calc");

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In reply to Re: test fails on 64bit uselongdouble Perl by ikegami
in thread test fails on 64bit uselongdouble Perl by frankcox

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