Blaster is a simple
application that illustrates Windows NT 5.0’s support of the IrDA protocol.
IrDA provides reliable point to point connectivity between 2 computers equipped
with infrared transceivers. Blaster uses the WinSock API with the IrDA address
family to setup a single connection and "blast" random data to a peer
machine that is also running blaster.
Blaster can be used
during the development of Winsock application or OEM IrDA NDIS drivers to get
an initial impression of performance.
To build BLASTER.EXE,
select either the checked or free DDK environment, change to the directory
BLASTER and type BUILD.
RUNNING THE SAMPLE
Copy BLASTER.EXE the test
machine and run it.
IrDA Winsock applications
are discussed in greater detail in the .DOC files included in the IrDA section
of the DDK samples.
Files Description
BLASTER.HTM The documentation for this sample (this file).SOURCES The generic file for building the code sample.
BLASTER.C The Source for blaster.
BLASTER.RC The resource file for blaster.MAKEFILE The standard DDK makefile.
RESOURCE.H C Defines for blaster.RESRC1.H More C Defines.
The major topics covered
in this tour are:
The majority of code in
this sample is actually devoted to window setup. The heart of the application
and the source of most interest to the reader are the functions SendThread() and RecvThread().
All of the functionality required for IrDA connections are encapsulated there.
The application itself is very simple. On startup, RecvThread()
creates a socket to listen for incoming IrDA connections. When the user clicks
the only button in the interface, SendThread() is invoked to enumerate available devices
and establish a connection with the first visible device. It will proceed to ‘blast’
data through this connection, and then close it.
Infrared Devices which
are in range will be enumerated when the user calls getsockopt()
with the parameters of SOL_IRLMP and IRLMP_ENUMDEVICES. Note that
no special coding is required if the computer has more than one IrDA adapter.
The protocol will automatically query for all visible devices on all IrDA
adapters present, and return them in a single call. Note that if a device is
visible to more than one adapter, it may be presented twice in the list.
Special notice is made
here that, unlike other Winsock protocol families, no call to bind() is required before calling connect().
Bind() is normally used to insure the
socket is correctly bound to a local address, generally for cases of multiple
local adapters. The IrDA protocol abstracts multiple adapters so that this is
not necessary. All context information needed to force the connection through
the correct adapter is contained in the SOCKADDR_IRDA structure provided
to connect(), in these fields: irdaDeviceID and irdaDeviceName.
If you do attempt to bind() on an
outbound connection, the connect() will return an error.