diff --git a/postgres.d b/postgres.d
index 23f9820..6ee166e 100644
--- a/postgres.d
+++ b/postgres.d
@@ -41,7 +41,7 @@ class PostgreSql : Database {
 
 	string escape(string sqlData) {
 		char* buffer = (new char[sqlData.length * 2 + 1]).ptr;
-		int size = PQescapeString (buffer, sqlData.ptr, sqlData.length);
+		ulong size = PQescapeString (buffer, sqlData.ptr, sqlData.length);
 
 		string ret = assumeUnique(buffer[0..size]);
 
@@ -167,8 +167,8 @@ string copyCString(const char* c, int actualLength = -1) {
 }
 
 extern(C) {
-	struct PGconn;
-	struct PGresult;
+	struct PGconn {};
+	struct PGresult {};
 
 	void PQfinish(PGconn*);
 	PGconn* PQconnectdb(const char*);