W&T 57630, Manual

Page: 110 / 211

110
W&T
TCP / UDP - Binary
WORD send_sequence;
WORD rec_sequence;
WORD struct_typ;
WORD length;
WORD set_bits;
WORD value;
} SETBIT;
The Variables are in this case byte-aligned „Lowbyte First“ in
memory.
To achieve byte alignment even for structures consisting of dif-
ferent variable types, please use the compiler option #pragma
pack(1).
#pragma pack(1);
typedef struct _COUNTER
{
word send_sequence;
word rec_sequence;
word struct_typ;
word length;
word counter_index;
long counter_value
} COUNTER;
#pragma pack()
Byte alignment in memory is important so that for example the
sequence of bytes resulting from passing a pointer to the
structure can be inserted directly into a TCP packet.
Visual Basic 5 and 6
Visual Basic offers the programmer the every easy-to-use
Winsock control element for network communication via TCP/
IP.
Unfortunately the VB Winsock control element does not allow
working with structures. Instead, data communication is handled
using string variables.