Apple Network Setup - Manual (Page 50)

C H A P T E R 2
Using Network Setup
50 Protocol-specific Topics
■ kOTCfgTCPDNSServersListPref , which contains the list of configured DNS
servers. For details, see OTCfgTCPDNSServersList (page 116).
■ kOTCfgTCPSearchDomainsPref , which contains the list of additional domains to
be searched. For details, see OTCfgTCPSearchDomains (page 120).
■ kOTCfgTCPUnloadAttrPref , which specifies how TCP/IP loads and unloads.
For details, see OTCfgTCPUnloadAttr (page 121).
■ kOTCfgTCPLocksPref , which is used by the TCP/IP control panel to remember
which preferences are locked. For details, see OTCfgTCPLocks (page 116).
The only complex preference in a TCP/IP network connection entity is the
kOTCfgTCPInterfacesPref preference. The data for this preference is packed in
an unusual way that makes the preference tricky to access from C. To help solve
this problem, Network Setup declares two sets of C structures for this
preference.
■ OTCfgTCPInterfacesPacked and OTCfgTCPInterfacesPackedPart help you
access the preference in its packed format.
■ OTCfgTCPInterfacesUnpacked is an unpacked form of the preference that you
can use internally within your code. When you read the preference, you can
unpack it into this structure. You can then manipulate the unpacked
structure and only pack it again when you write it.
Listing 2-16 provides sample code that unpacks and packs a
kOTCfgTCPInterfacesPref preference.
Listing 2-16 Packing and unpacking the kOTCfgTCPInterfacesPref preference
static OSStatus MyPackTCPInterfacesPref(const OTCfgTCPInterfacesUnpacked *unpackedPref,
OTCfgTCPInterfacesPacked *packedPref,
ByteCount *packedPrefSize)
{
UInt8 *cursor;
assert(unpackedPref != nil);
assert(packedPref != nil);
assert(packedPrefSize != nil);
// Start the cursor at the beginning of the packed preference.