diff -r a0573014ff4f -r c42949cfdd92 project_files/frontlib/ipcconn.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/project_files/frontlib/ipcconn.h	Thu May 31 18:54:40 2012 +0200
@@ -0,0 +1,67 @@
+/*
+ * Low-level protocol support for the IPC connection to the engine.
+ */
+
+#ifndef IPCCONN_H_
+#define IPCCONN_H_
+
+#include <stddef.h>
+
+typedef enum {IPC_NOT_CONNECTED, IPC_LISTENING, IPC_CONNECTED} IpcConnState;
+
+/**
+ * Called by flib_init(). Initialize everything related to ipc.
+ */
+void flib_ipcconn_init();
+
+/**
+ * Called by flib_quit(). Free resources and shut down.
+ */
+void flib_ipcconn_quit();
+
+/**
+ * Start listening for a connection from the engine. The system has to be in state
+ * IPC_NOT_CONNECTED when calling this function.
+ *
+ * Returns the port we started listening on, or a negative value if there is an error.
+ *
+ * We stop listening once a connection has been established, so if you want to start
+ * the engine again and talk to it you need to call this function again after the old
+ * connection is closed.
+ */
+int flib_ipcconn_listen();
+
+/**
+ * Close the current IPC connection and/or stop listening for an incoming one.
+ * This also discards all unread messages.
+ */
+void flib_ipcconn_close();
+
+/**
+ * Determine the current connection state
+ */
+IpcConnState flib_ipcconn_state();
+
+/**
+ * Receive a single message (up to 255 bytes) and copy it into the data buffer.
+ * Returns the length of the received message, a negative value if no message could
+ * be read.
+ */
+int flib_ipcconn_recv_message(void *data);
+
+/**
+ * Write a single message (up to 255 bytes) to the engine. This call blocks until the
+ * message is completely written or the connection is closed or an error occurs.
+ *
+ * Calling this function in a state other than IPC_CONNECTED will fail immediately.
+ * Returns a negative value on failure.
+ */
+int flib_ipcconn_send_message(void *data, size_t len);
+
+/**
+ * Call regularly to allow background work to proceed
+ */
+void flib_ipcconn_tick();
+
+#endif /* IPCCONN_H_ */
+