Synopsis: 

       task_id=msg_senderid()

Arguments: 

       none

Description: This function returns the Telecom Engine task id for the task that sent the last message to the calling task.    This function can be used to determine where to send a return message to after receiving a message.

For example:

       msg_str=msg_read(30);

       // If a message was received..

       if(msg_str strneq "")

               // Get the task ID of the sending task

               return_id=msg_senderid();

               // Send back an ACK message

               msg_send(return_id,"ACK");

       endif

Returns:   Returns the task ID of the task that sent the last message received by the calling task or -1 if no messages have been received.