Returning using an IOV array that points to your data

Sometimes you'll want to reply with a header followed by one of N buffers, where the buffer used will differ each time you reply. To do this, you can set up an IOV array whose elements point to the header and to a buffer.

The context structure already has an IOV array. If you want the resource manager library to do your reply for you, then you must use this array. But the array must contain enough elements for your needs. To ensure that this is the case, set the nparts_max member of the resmgr_attr_t structure that you passed to resmgr_attach() when you registered your name in the pathname space.

The following example assumes that the variable i contains the offset into the array of buffers of the desired buffer to reply with. The 2 in _RESMGR_NPARTS(2) tells the library how many elements in ctp->iov to reply with.

my_header_t     header;
a_buffer_t      buffers[N];


SETIOV(&ctp->iov[0], &header, sizeof(header));
SETIOV(&ctp->iov[1], &buffers[i], sizeof(buffers[i]));
return (_RESMGR_NPARTS(2));