diff --git a/rtmp/socket.go b/rtmp/socket.go
index 31542ab8..e8ab1e02 100644
--- a/rtmp/socket.go
+++ b/rtmp/socket.go
@@ -189,7 +189,7 @@ func C_RTMPSockBuf_Fill(sb *C_RTMPSockBuf) int {
 		sb.sb_start = 0
 	}
 
-	nBytes := C.long((len(sb.sb_buf) - 1) - (sb.sb_size + sb.sb_start))
+	nBytes := C.ssize_t((len(sb.sb_buf) - 1) - (sb.sb_size + sb.sb_start))
 	nBytes, err := C.recv(C.int(sb.sb_socket), unsafe.Pointer(&sb.sb_buf[sb.sb_start+sb.sb_size]), C.size_t(nBytes), 0)
 	if nBytes == -1 {
 		log.Printf("C_RTMPSockBuf_Fill: recv error: %v", err)
@@ -208,7 +208,7 @@ func C_RTMPSockBuf_Fill(sb *C_RTMPSockBuf) int {
 // rtmp.c +4297
 // TODO replace send with golang net connection send
 func C_RTMPSockBuf_Send(sb *C_RTMPSockBuf, buf []byte) int32 {
-	return int32(C.send(C.int(sb.sb_socket), unsafe.Pointer(bAddr(buf)), C.ulong(len(buf)), 0))
+	return int32(C.send(C.int(sb.sb_socket), unsafe.Pointer(bAddr(buf)), C.size_t(len(buf)), 0))
 }
 
 // int