#ifndef _sgp4ext_
#define _sgp4ext_
#include <math.h>
#include <string.h>
#include "sgp4unit.h"
extern "C" {
double sgn(double x);
double mag(double x[3]);
void cross(double vec1[3], double vec2[3], double outvec[3]);
double dot(double x[3], double y[3]);
double angle(double vec1[3], double vec2[3]);
void newtonnu(double ecc, double nu, double &e0, double &m);
double asinh(double xval);
void rv2coe(double r[3], double v[3], double mu, double &p, double &a,
double &ecc, double &incl, double &omega, double &argp, double &nu,
double &m, double &arglat, double &truelon, double &lonper);
void jday(int year, int mon, int day, int hr, int minute, double sec,
double &jd);
void days2mdhms(int year, double days, int &mon, int &day, int &hr, int &minute,
double &sec);
void invjday(double jd, int &year, int &mon, int &day, int &hr,
int &minute, double &sec);
}
#endif