Function qags

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