Returning with a single buffer containing data

An example of this would be replying to a read() where all the data existed in a single buffer. You'll typically see this done in two ways:

return (_RESMGR_PTR(ctp, buffer, nbytes));

And:

SETIOV (ctp->iov, buffer, nbytes);
return (_RESMGR_NPARTS(1));

The first method, using the _RESMGR_PTR() macro, is just a convenience for the second method where a single IOV is returned.