Re: long double support on 80x86 C++ Win32 compilers

Bruce Dawson <comments@cygnus-software.com> writes:
> [ who supports long double values on x86 ? ]


The Win32 port of gcc does (cygwin32). The compiler is freely available.


> The following (C - sorry) test program can be used to see how large a
> floating point number fits into a compiler's long double. An eight
> byte double overflows around 1e350, a ten byte double overflows far
> beyond that.


> #include <stdio.h>


> int main(int argc, char *argv[])
> {
> long double x = 123456789;
> for (int i = 0; i < 10; i++)
> {
> x *= x;
> printf("x = %g\n", x);
                                      ^^^^
                          Should be %Lg
> }
> return 0;
> }


This program is buggy. See above. At least on linux/x86 it will print wrong
values (but gcc catches it of course when compiled with -Wall)


-Andi
--

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