GSL特殊函数

#define GSL_DLL#include <stdio.h>#include <gsl/gsl_sf_bessel.h>#pragma comment(lib, "libgsl_dll_d.lib")#pragma comment(lib, "libgslcblas_dll_d.lib")intmain (void){  double x = 5.0;  double expected = -0.17759677131433830434739701;    double y = gsl_sf_bessel_J0 (x);  printf ("J0(5.0) = %.18f\n", y);  printf ("exact   = %.18f\n", expected);  return 0;}