[混编] Call Fortran subroutine from C encounter“Undefined ... ”

Integer Function Add(A,B)  Bind(C,Name="Add")!//要返回的话，请用 Function
  use , Intrinsic :: ISO_C_Binding
  implicit none
  integer , value :: A , B !/c#默认是传值，而fortran默认传址。因此要用value修饰
  Add = a + b !// Add（函数名）用于返回，而不能写 return a+b
end Function Add

#include <stdio.h>
extern "C" int Add(int A,int B);
int main()
{
      int c = Add(1,2);
      printf("c=%d\n",c);
      return 0;
}

test: test.o subf.o
	icc -O2 -o test *.o
test.o:
	icc -c test.c
subf.o:
	ifort -c subf.f90

test.o: In function `main':
test.cpp:(.text+0x35): undefined reference to `Add(int, int)'
Makefile:5: recipe for target 'test' failed