diff --git a/ph7.go b/ph7.go
index 51bb6b0..c99a908 100644
--- a/ph7.go
+++ b/ph7.go
@@ -1,6 +1,7 @@
 package ph7
 
 /*
+#include <stdlib.h>
 #include "ph7.h"
 
 int engine_config_err_log(ph7 *pEngine, const char **pzPtr, int *pLen) {
@@ -14,6 +15,7 @@ int vm_extract_output(ph7_vm *pVm, const char **pzPtr, int *pLen) {
 import "C"
 import (
 	"fmt"
+	"io"
 )
 
 type ResultCode int
@@ -97,6 +99,7 @@ func (e Engine) ErrLog() (string, error) {
 
 func (e Engine) Compile(source []byte, phpOnly bool) (*VM, error) {
 	csource := C.CBytes(source)
+	defer C.free(csource)
 	vm := new(VM)
 	var flags C.int
 	if phpOnly {
@@ -107,7 +110,6 @@ func (e Engine) Compile(source []byte, phpOnly bool) (*VM, error) {
 		return nil, err
 	}
 
-	// TODO free csource
 	return vm, nil
 }
 
@@ -119,6 +121,10 @@ type VM struct {
 	ptr *C.ph7_vm
 }
 
+func (vm VM) SetOutputWriter(w io.Writer) error {
+	return nil
+}
+
 func (vm VM) ExtractOutput() (string, error) {
 	var s *C.char
 	var n C.int