1 package main
 2 
 3 import "fmt"
 4 /*
 5 #include <stdlib.h>
 6 #include <stdio.h>
 7 void hello()
 8 {
 9     printf("Hello World !\n");
10 }
11 */
12 import "C"
13 
14 func Hello() {
15     C.hello();
16 }
17 
18 
19 func Random() int {
20     return int(C.random())
21 }
22 
23 func Seed(i int) {
24     C.srandom(C.uint(i))
25 }
26 
27 func main () {
28     Seed(100)
29     fmt.Println("Random:", Random())
30     Hello()
31 }

$ go run cgo.go 
Random: 677741240
Hello World !