lib.go

package main

import "C"

func main() {}

//export Hello
func Hello() string {
	return "Hello"
}

//export Test
func Test() {
	println("export Test")
}

main.c

#include <stdio.h>
#include "libgo4c.h"
void main()
{
		   GoString str;
		   str = Hello();
		   Test();
		   printf("%d\n",str.n);
 }

build.sh

go mod init go4c
go build -buildmode=c-shared -o libgo4c.so lib.go

  go build -buildmode=c-archive -o libgo4c.a lib.go

gcc main.c -o test -I./ -L./ -lgo4c
export LD_LIBRARY_PATH=`pwd`
./test