AMX DESIGN XPRESS V 1.5 - PROGRAMMER GUIDE User's Guide download pdf (Page 45)

KwikNet Overview

DAK

The client calls kn_socket() to create a streaming socket. It then calls kn_bind() to

bind itself to the socket, allowing KwikNet to assign a port number and IP address.

The client then calls kn_connect() to connect to the server with port number 5001 and

IP address 192.168.1.73. Note that the client has to know the port number of the server

to which it is trying to connect. The IP address of the server happens to be the IP address

assigned to the Ethernet network predefined in the

KwikNet Library. The sample

illustrates the use of procedure

kn_inet_addr() to convert an IP address in dotted

decimal form to an equivalent network compatible form.

Once the connection has been established, the client sends the long value 26 (defined as

SAMMSGSZ) as a 4 byte message to the server. The number SAMMSGSZ is the number of

data bytes which the client intends to send to the server. It happens to be the number of

characters in the alphabet, the data which will be sent.

The client then uses procedure kn_recv() to receive a 4 byte message, a long value

which confirms the length of the block of data which the server is willing to accept from

the client.

The client then prepares to send the 26 characters of the alphabet to the server. The client

does so using the kn_writev() procedure which permits the data to be gathered from

disjoint locations in memory but delivered as a sequential byte stream. The 26 characters

are gathered from the following two strings: 10 from the first and 16 from the second.

"ABCDEFGHIJ1234"

"KLMNOPQRSTUVWXYZ5678"

The client then waits for an echo from the server of the data actually received by the

server. The client does so using the kn_readv() procedure which permits the received

data to be scattered into disjoint locations in memory even though received as a

sequential byte stream. The data is scattered into a zero filled character buffer: 7 bytes at

offset 0, 11 bytes at offset 20 and 8 bytes at offset 40. The three strings at offsets 0, 20

and 40 are then expected to match as follows.

"ABCDEFG"

"HIJKLMNOPQR"

"STUVWXYZ"

Finally, the client uses kn_shutdown() to terminate all send operations on its connected

socket and then repetitively calls kn_recv() until all unexpected data, if any, from the

server has been discarded. The socket is then closed using kn_close().

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AMX DESIGN XPRESS V 1.5 - PROGRAMMER GUIDE User's Guide Page 45