In this case, you give the client the data and get the resource manager library to do the reply for you. However, the reply data won't be valid by that time. For example, if the reply data was in a buffer that you wanted to free before returning, you could use the following:
resmgr_msgwrite (ctp, buffer, nbytes, 0); free (buffer); return (EOK);
The resmgr_msgwrite() function copies the contents of buffer into the client's reply buffer immediately. Note that a reply is still required in order to unblock the client so it can examine the data. Next we free the buffer. Finally, we return to the resource manager library such that it does a reply with zero-length data. Since the reply is of zero length, it doesn't overwrite the data already written into the client's reply buffer. When the client returns from its send call, the data is there waiting for it.