I am writing a resource manager and am trying to implement a blocking read.  I am saving the rcvid from the original 
read request.  

I have used select_attach to wait for data from another file descriptor.  When that descriptor comes ready, my attached 
function reads the data from that file descriptor.  I would like to satisfy the original read request by using 
resmgr_msg_again and my saved rcvid, however the context structure passed in is a select_context_t instead of the 
resmgr_context_t that resmgr_msg_again requires.

The compiler doesn't like me passing in the select_context_t, which seems reasonable.  Is there any way for me to obtain
 the resmgr_context_t from the select_context_t pointer I have?  

Is there a better way to do this in general?