diff --git a/transaction.go b/transaction.go
index ae052c8..9dba072 100644
--- a/transaction.go
+++ b/transaction.go
@@ -4,21 +4,7 @@ package pam
 //#cgo CFLAGS: -Wall -std=c99
 //#cgo LDFLAGS: -lpam
 //
-//#include <security/pam_appl.h>
-//#include <stdlib.h>
-//#include <stdint.h>
-//
-//#ifdef PAM_BINARY_PROMPT
-//#define BINARY_PROMPT_IS_SUPPORTED 1
-//#else
-//#include <limits.h>
-//#define PAM_BINARY_PROMPT INT_MAX
-//#define BINARY_PROMPT_IS_SUPPORTED 0
-//#endif
-//
-//void init_pam_conv(struct pam_conv *conv, uintptr_t);
-//int pam_start_confdir(const char *service_name, const char *user, const struct pam_conv *pam_conversation, const char *confdir, pam_handle_t **pamh) __attribute__ ((weak));
-//int check_pam_start_confdir(void);
+//#include "transaction.h"
 import "C"
 
 import (
@@ -89,16 +75,24 @@ func (f ConversationFunc) RespondPAM(s Style, msg string) (string, error) {
 	return f(s, msg)
 }
 
-// cbPAMConv is a wrapper for the conversation callback function.
+// _go_pam_conv_handler is a C wrapper for the conversation callback function.
 //
-//export cbPAMConv
-func cbPAMConv(s C.int, msg *C.char, c C.uintptr_t) (*C.char, C.int) {
+//export _go_pam_conv_handler
+func _go_pam_conv_handler(msg *C.struct_pam_message, c C.uintptr_t, outMsg **C.char) C.int {
+	convHandler, ok := cgo.Handle(c).Value().(ConversationHandler)
+	if !ok || convHandler == nil {
+		return C.int(ErrConv)
+	}
+	replyMsg, r := pamConvHandler(Style(msg.msg_style), msg.msg, convHandler)
+	*outMsg = replyMsg
+	return r
+}
+
+// pamConvHandler is a Go wrapper for the conversation callback function.
+func pamConvHandler(style Style, msg *C.char, handler ConversationHandler) (*C.char, C.int) {
 	var r string
 	var err error
-	v := cgo.Handle(c).Value()
-	style := Style(s)
-	var handler ConversationHandler
-	switch cb := v.(type) {
+	switch cb := handler.(type) {
 	case BinaryConversationHandler:
 		if style == BinaryPrompt {
 			bytes, err := cb.RespondPAMBinary(BinaryPointer(msg))
@@ -116,8 +110,7 @@ func cbPAMConv(s C.int, msg *C.char, c C.uintptr_t) (*C.char, C.int) {
 			return nil, C.int(ErrConv)
 		}
 		handler = cb
-	}
-	if handler == nil {
+	default:
 		return nil, C.int(ErrConv)
 	}
 	r, err = handler.RespondPAM(style, C.GoString(msg))
diff --git a/transaction.c b/transaction.h
similarity index 62%
rename from transaction.c
rename to transaction.h
index 8abed03..88d2766 100644
--- a/transaction.c
+++ b/transaction.h
@@ -1,15 +1,25 @@
-#include "_cgo_export.h"
 #include <security/pam_appl.h>
 #include <stdint.h>
+#include <stdlib.h>
 #include <string.h>
 
+#ifdef PAM_BINARY_PROMPT
+#define BINARY_PROMPT_IS_SUPPORTED 1
+#else
+#include <limits.h>
+#define PAM_BINARY_PROMPT INT_MAX
+#define BINARY_PROMPT_IS_SUPPORTED 0
+#endif
+
 #ifdef __sun
 #define PAM_CONST
 #else
 #define PAM_CONST const
 #endif
 
-int cb_pam_conv(int num_msg, PAM_CONST struct pam_message **msg, struct pam_response **resp, void *appdata_ptr)
+extern int _go_pam_conv_handler(struct pam_message *, uintptr_t, char **reply);
+
+static inline int cb_pam_conv(int num_msg, PAM_CONST struct pam_message **msg, struct pam_response **resp, void *appdata_ptr)
 {
 	if (num_msg <= 0 || num_msg > PAM_MAX_NUM_MSG)
 		return PAM_CONV_ERR;
@@ -19,11 +29,9 @@ int cb_pam_conv(int num_msg, PAM_CONST struct pam_message **msg, struct pam_resp
 		return PAM_BUF_ERR;
 
 	for (size_t i = 0; i < num_msg; ++i) {
-		struct cbPAMConv_return result = cbPAMConv(msg[i]->msg_style, (char *)msg[i]->msg, (uintptr_t)appdata_ptr);
-		if (result.r1 != PAM_SUCCESS)
+		int result = _go_pam_conv_handler((struct pam_message *)msg[i], (uintptr_t)appdata_ptr, &(*resp)[i].resp);
+		if (result != PAM_SUCCESS)
 			goto error;
-
-		(*resp)[i].resp = result.r0;
 	}
 
 	return PAM_SUCCESS;
@@ -41,7 +49,7 @@ error:
 	return PAM_CONV_ERR;
 }
 
-void init_pam_conv(struct pam_conv *conv, uintptr_t appdata)
+static inline void init_pam_conv(struct pam_conv *conv, uintptr_t appdata)
 {
 	conv->conv = cb_pam_conv;
 	conv->appdata_ptr = (void *)appdata;
@@ -52,7 +60,7 @@ void init_pam_conv(struct pam_conv *conv, uintptr_t appdata)
 int pam_start_confdir(const char *service_name, const char *user, const struct pam_conv *pam_conversation,
 		      const char *confdir, pam_handle_t **pamh) __attribute__((weak));
 
-int check_pam_start_confdir(void)
+static inline int check_pam_start_confdir(void)
 {
 	if (pam_start_confdir == NULL)
 		return 1;