[interfacekit] Re: Port Messaging

>>As Dianne said recently most messaing to the app_server is
>>not BMEssage based, however.  Though you'd entitled to answer
>>by pointing out that this paprticular kind of message (CREATE_APP)
>>is not a bottleneck/CPU-intensive one.
>I saw this kind of usage done in AtheOS and I thought it might be 
useful. 
>What would you suggest? Obviously, this is not my area of expertise.

Well, for the particular example you're giving, you could do it the hard 
way:

        int32 msgSize =
                sizeof (int32) +       // for the CREATE_APP opcode
                strlen(signature) + 1  // one extra for null terminator
                sizeof (int32);        // for the port id

        uchar* buffer = new uchar[msgSize];
        uchar* bp = buffer;
        *(int32*)bp = CREATE_APP;
        bp += sizeof (int32);
        strcpy(bp, signature);
        bp += strlen(signature);
        *bp = '\0';
        ++bp;
        *(int32*)bp = messageport;

        write_port(serverport, CREATE_APP, buffer, msgSize);

But that would just be a pain in the rear. =)  I think the smartest 
thing to do is for us to create a class which abstracts the buffer 
management, so we can do this:

        BAppServerLink Server(serverport);
        Server << CREATE_APP;
        Server << signature;
        Server << messageport;
        Server.Flush();

Or perhaps

        BAppServerLink Server(serverport);
        Server.SetOpcode(CREATE_APP);
        Server << signature;
        Server << messageport;
        Server.Flush();

Anyway, I'm sure you get the idea.  As Cedric pointed out, you could get 
away with using BMessage for in this particular instance, but generally 
all messaging to app_server should be done as straight binary data 
streams.  Communication with app_server needs to be as close to 
real-time as possible, and BMessages just aren't going to cut it there.

e

Data is not information, and information is not knowledge: knowledge is 
not understanding, and understanding is not wisdom.
        - Philip Adams

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