Cgo Testcase

Makefile

include $(GOROOT)/src/Make.inc

TARG=testcase

CGOFILES=\
	testcase.go\

CGO_OFILES=\
	testcase.o\

include $(GOROOT)/src/Make.pkg

testcase.c

#include "testcase.h"
#include "_cgo_export.h"

void CallC(struct MyData *data) {
	Callback(data);
}

testcase.go

package testcase

import (
	"fmt"
	// "unsafe"
)

// #cgo CFLAGS: -I.
// #include "testcase.h"
import "C"

func CallMe()  {
	data := C.struct_MyData {4}
	C.CallC(&data)
}

//export Callback
func Callback(data *C.struct_MyData) {
	fmt.Printf("Data: %d\n", data.Number)
}

// // This however works:
// //export Callback
// func Callback(data unsafe.Pointer) {
// 	fmt.Printf("Data: %d\n", ((*C.struct_MyData)(data)).Number)
// }

testcase.h

#ifndef TESTCASE_H
#define TESTCASE_H

struct MyData {
	int Number;
};

void CallC(struct MyData *data);

#endif // TESTCASE_H