cgo 之 go 访问c 的数据 - int

以int 为例子. 适合int系列, float double .
不适用于字符串.

package main

//#include <stdio.h>
//static int m;
//int* get_m_addr(){return &m;}
//void show_m(){printf("m=%d\n",m);}
//void set_m(void *p,int x) {*(int*)p = x;}
import "C"
import "unsafe"

func main() {
    t := C.get_m_addr()

    *t = 5
    C.show_m();
    x := 100
    *t = C.int(x)

    C.show_m()

    y := 200

    C.set_m(unsafe.Pointer(t),C.int(y))
    C.show_m()
}