atan2 incorrect about libfixmath HOT 5 OPEN

I cannot seem to reproduce this bug.

For me the result is 34481, which is 0.5 % error. This is within the expected 
limits.

See attached test.c, I compiled it under x86_64 using GCC with this command:
gcc -o test test.c fix16.c fix16_trig.c fix16_sqrt.c 
./test
sqrt: 113512 atan2: 34481

The compiler i'm using is MSVC 2008 Express Edition version 9.0

Can you compile the test.c included earlier and tell us its output?

sqrt: 113512 atan2: -2147432177

I'm also having difficulties with atan2. Here is the code I use to compare 
atan2 for double and Fix16. I cannot expect Fix16 to be as accurate as double, 
but there seems to be an offset of about 0.1 pi for some values. Here is the 
code I use:

#include <cmath>
#include <fstream>
#include <iostream>

#include <fix16.h>
#include <fix16.hpp>

int main()
{
  unsigned int n = 1000;
  std::ofstream file("out.dat");
  std::ostream& out(file);//(std::cout);
  for(unsigned int i = 0; i <= n; i++)
  {
    double d = M_PI/2.*i/1000;
    double s = sin(d);
    double c = cos(d);
    double a = atan2(s,c);
    Fix16 df(d);
    Fix16 sf(df.sin());
    Fix16 cf(df.cos());
    Fix16 af(sf.atan2(cf));
    out << d
        << " " << a
        << " " << (double)af
        << std::endl;
  }
  return 0;
}

I used gnuplot for plotting the results, here is the command:

plot "out.dat" u 1:2 w l title 'double', "out.dat" u 1:3 w l title 'Fix16'

I have attached the plot.