Improve the documentation of the RenderScript API.

Only the explanations should be changing.

Change-Id: I889b366e3be44f5ac7f44a199e4b9a47353665e2
diff --git a/scriptc/rs_io.rsh b/scriptc/rs_io.rsh
index 7bb7a49..d14af11 100644
--- a/scriptc/rs_io.rsh
+++ b/scriptc/rs_io.rsh
@@ -17,9 +17,11 @@
 // Don't edit this file!  It is auto-generated by frameworks/rs/api/generate.sh.
 
 /*
- * rs_io.rsh: Input/output functions
+ * rs_io.rsh: Input/Output Functions
  *
- * TODO Add documentation
+ * These functions are used to:
+ * - Send information to the Java client, and
+ * - Send the processed allocation or receive the next allocation to process.
  */
 
 #ifndef RENDERSCRIPT_RS_IO_RSH
@@ -31,7 +33,7 @@
  * Receive a new set of contents from the queue.
  *
  * Parameters:
- *   a: allocation to work on
+ *   a: Allocation to work on.
  */
 #if (defined(RS_VERSION) && (RS_VERSION >= 16))
 extern void __attribute__((overloadable))
@@ -44,7 +46,7 @@
  * Send the contents of the Allocation to the queue.
  *
  * Parameters:
- *   a: allocation to work on
+ *   a: Allocation to work on.
  */
 #if (defined(RS_VERSION) && (RS_VERSION >= 16))
 extern void __attribute__((overloadable))
@@ -52,9 +54,19 @@
 #endif
 
 /*
- * Send a message back to the client.  Will not block and returns true
- * if the message was sendable and false if the fifo was full.
- * A message ID is required.  Data payload is optional.
+ * rsSendToClient: Send a message to the client, non-blocking
+ *
+ * Sends a message back to the client.  This call does not block.
+ * It returns true if the message was sent and false if the
+ * message queue is full.
+ *
+ * A message ID is required.  The data payload is optional.
+ *
+ * See RenderScript.RSMessageHandler.
+ *
+ * Parameters:
+ *   data: Application specific data.
+ *   len: Length of the data, in bytes.
  */
 extern bool __attribute__((overloadable))
     rsSendToClient(int cmdID);
@@ -63,8 +75,20 @@
     rsSendToClient(int cmdID, const void* data, uint len);
 
 /*
- * Send a message back to the client, blocking until the message is queued.
- * A message ID is required.  Data payload is optional.
+ * rsSendToClientBlocking: Send a message to the client, blocking
+ *
+ * Sends a message back to the client.  This function will block
+ * until there is room on the message queue for this message.
+ * This function may return before the message was delivered and
+ * processed by the client.
+ *
+ * A message ID is required.  The data payload is optional.
+ *
+ * See RenderScript.RSMessageHandler.
+ *
+ * Parameters:
+ *   data: Application specific data.
+ *   len: Length of the data, in bytes.
  */
 extern void __attribute__((overloadable))
     rsSendToClientBlocking(int cmdID);