Function qag

void qag(Real, Func) (
  Func f,
  Real a,
  Real b,
  Real epsabs,
  Real epsrel,
  int key,
  out Real result,
  out Real abserr,
  out int neval,
  out int ier,
  int limit,
  int lenw,
  out int last,
  int* iwork,
  Real* work
);