1 files changed, 57 insertions, 0 deletions
diff --git a/erts/example/pg_async.erl b/erts/example/pg_async.erl
new file mode 100644
index 0000000000..10506bfe9f
--- /dev/null
+++ b/erts/example/pg_async.erl
@@ -0,0 +1,57 @@
+%%
+%% %CopyrightBegin%
+%% 
+%% Copyright Ericsson AB 2006-2009. All Rights Reserved.
+%% 
+%% The contents of this file are subject to the Erlang Public License,
+%% Version 1.1, (the "License"); you may not use this file except in
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved online at http://www.erlang.org/.
+%% 
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and limitations
+%% under the License.
+%% 
+%% %CopyrightEnd%
+%%
+-module(pg_async).
+
+-define(DRV_CONNECT, $C).
+-define(DRV_DISCONNECT, $D).
+-define(DRV_SELECT, $S).
+
+-export([connect/1, disconnect/1, select/2]).
+
+connect(ConnectStr) ->
+    case erl_ddll:load_driver(".", "pg_async") of
+	ok -> ok;
+	{error, already_loaded} -> ok;
+	E -> exit(E)
+    end,
+    Port = open_port({spawn, ?MODULE}, [binary]),
+    port_control(Port, ?DRV_CONNECT, ConnectStr),
+    case return_port_data(Port) of
+	ok -> 
+	    {ok, Port};
+	Error ->
+	    Error
+    end.    
+
+disconnect(Port) ->
+    port_control(Port, ?DRV_DISCONNECT, ""),
+    R = return_port_data(Port),
+    port_close(Port),
+    R.
+
+select(Port, Query) ->
+    port_control(Port, ?DRV_SELECT, Query),
+    return_port_data(Port).
+
+return_port_data(Port) ->
+    receive
+	{Port, {data, Data}} ->
+	    binary_to_term(Data)
+    end.
+