vsTASKER 7 Tutorial
×
Menu
Index
Search
 
   
   
   
 
Copyright VirtualSim 2004-2020 - All rights reserved

LAN

 
 
 
 
Each message sent or received  through a SockItem must have a predefined header made of two integers (so 8 bytes), organized as this:
 
unsigned short source, type;
unsigned int   size;
 
Source is the any value used to qualify the message provider (is several devices are writing into the same port).
Type: specify the type of the message for casting it properly
Size: is the total length in bytes of the message, for reading the buffer correctly.
 
So, all user data structure that must be passed or read through a SockItem must be defined as a class inheriting from a base class (MsgData) of vsTASKER.
This base class can be found in /include/engine/vt_sockets.h
 
For example, if a message must be made of a character string and a value, it should be defined this way:
 
class myMessage : public MsgData 
{
  public: myMessage() { size = sizeof(*this); type = 123; }
 
  char  label[20];
  float value;
};
 
Then, sending such a message would be done, from a SockItem code, like that:
 
MyMessage my_mess;
strcpy(my_mess.label, "foo");
my_mess.value = 12.332;
send(my_mess);
 
And receiving such a message from outside would be done, in a SockItem,like that:
 
if (msgData->type == 123) {
   MyMessage* my_mess = (MyMessage*) msgData;
   printf("%s = %f\n", my_mess->label, my_mess->value);
}