#include <float.h>
#include <math.h>
#include <stdint.h>

#if FLT_EVAL_METHOD==0 || FLT_EVAL_METHOD==1
#define EPS DBL_EPSILON
#elif FLT_EVAL_METHOD==2
#define EPS LDBL_EPSILON
#endif
static const double_t toint = 1/EPS;

double rint(double x)
{
        union {double f; uint64_t i;} u = {x};
        int e = u.i>>52 & 0x7ff;
        int s = u.i>>63;
        double_t y;

        if (e >= 0x3ff+52)
                return x;
        if (s)
                y = x - toint + toint;
        else
                y = x + toint - toint;
        if (y == 0)
                return s ? -0.0 : 0;
        return y;
}