W&T 57630, Руководство пользователя

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103
W&T
TCP / UDP - Binary
Subject to errors and modifications:
client/server applications under TCP/IP can be downloaded
from our homepage at http://www.wut.de.
5.6.7 Definition of the IO structures
In order to uniquely identify and process the contents of a packet
in BINARY mode, all the data must be sent to the Web-IO in the
form of these IO structures, regardless of whether you are using
50xxx-compatible or Default mode.
All structures begin with the same header, which consists of the
following 4 WORDs (16bit Integer):
send_sequence and rec_sequence are only filled if you want to
implement control of the packet sequence yourself in UDP mode.
Otherwise these values are always 0 and must not be omitted!
The value struct_type identifies the contents of the structure after
the first 4 WORDs and indicates the total length of the structure in
bytes, i.e., including the first 4 WORDs. This results in the
following general packet structure:
Struktur Construction WORD send_sequenz always 0
WORD rec_sequenz always 0
WORD struct_type identification of structur
WORD length length of structure
VARIBLE ........... further variables
......... ........... further variables
1
Note: The following applies to all IO structures:
A word corresponds to 16bit integer.
A char corresponds to one byte (8bits)
A long corresponds to a 32bit integer
Hexadecimal format 0x in front of the value
In the next sections the individual structures used for name
are declared and explained and the corresponding values of the
variables
send_sequence, rec_sequence, struct_type and
length , with which each packet begins, are given.