Getting Started with QNX Neutrino - QNX Software Systems

© 2009, QNX Software Systems GmbH & Co. KG. Handler routines
_RESMGR_NOREPLY
_RESMGR_NPARTS (n)
Indicates to the resource manager library that it should not
perform the MsgReplyv() — the assumption is that you’ve either
performed it yourself in your handler function, or that you’re
going to do it some time later.
The resource manager library should return an n-part IOV when it
does the MsgReplyv() (the IOV is located in ctp -> iov). Your
function is responsible for filling in the iov member of the ctp
structure, and then returning _RESMGR_NPARTS with the correct
number of parts.
The iov member of ctp is allocated dynamically, so it must be big enough to hold the
number of array elements that you’re writing into the iov member! See the section
“resmgr_attr_t control structure” above, for information on setting the
nparts_max member.
_RESMGR_DEFAULT
An errno value
_RESMGR_ERRNO (errno)
_RESMGR_PTR (ctp, addr, len)
This instructs the resource manager library to perform the
low-level default function (This is not the same as the
iofunc_*_default() functions!) You’d rarely ever use this return
value. In general, it causes the resource manager library to return
an errno of ENOSYS to the client, which indicates that the function
is not supported.
Indicates to the resource manager library that it should call
MsgError() with this value as the error parameter. This generally
causes the client function (e.g. open()) to return -1 and set errno
on the client side to the returned value.
(Deprecated) This return value had been used to “wrap” an errno
number as the return value of the message. For example, if a client
issued an open() request for a read-only device, it would be
appropriate to return the error value EROFS. Since this function is
deprecated, you can return the error number directly instead of
wrapping it with the _RESMGR_ERRNO macro (e.g., return
(EROFS); instead of the more cumbersome return
(_RESMGR_ERRNO (EROFS));.)
This is a convenience macro that accepts the context pointer ctp,
and fills its first IOV element to point to the address specified by
addr for the length specified by len, and then returns the equivalent
of _RESMGR_NPARTS (1) to the library. You’d generally use this
if you return single-part IOVs from your function.
April 30, 2009 Chapter 5 • Resource Managers 227