Getting Started with QNX Neutrino - QNX Software Systems

© 2009, QNX Software Systems GmbH & Co. KG. Writing a resource manager
lock_count
count
rcount
wcount
rlocks
wlocks
mmap_list
lock_list
list
list_size
nbytes
inode
uid
gid
mtime
atime
ctime
Indicates how many threads are trying to use this attributes structure.
A value of zero indicates that the structure is unlocked. A value of one
or more indicates that one or more threads are using the structure.
Indicates the number of OCBs that have this attributes structure open
for any reason. For example, if one client has an OCB open for read,
another client has another OCB open for read/write, and both OCBs
point to this attribute structure, then the value of count would be 2, to
indicate that two clients have this resource open.
Count readers. In the example given for count, rcount would also have
the value 2, because two clients have the resource open for reading.
Count writers. In the example given for count, wcount would have the
value 1, because only one of the clients has this resource open for
writing.
Indicates the number of OCBs that have read locks on the particular
resource. If zero, means there are no read locks, but there may be
write locks.
Same as rlocks but for write locks.
Used internally by POSIX iofunc_mmap_default().
Used internally by POSIX iofunc_lock_default().
Reserved for future use.
Size of area reserved by list.
Size of the resource, in bytes. For example, if this resource described
a particular file, and that file was 7756 bytes in size, then the nbytes
member would contain the number 7756.
Contains a file or resource serial number, that must be unique per
mountpoint. The inode should never be zero, because zero
traditionally indicates a file that’s not in use.
User ID of the owner of this resource.
Group ID of the owner of this resource.
File modification time, updated or at least invalidated whenever a
client write() is processed.
File access time, updated or at least invalidated whenever a client
read() that returns more than zero bytes is processed.
File change time, updated or at least invalidated whenever a client
write(), chown(), orchmod() is processed.
April 30, 2009 Chapter 5 • Resource Managers 223