[blitz] CxBroker_() - could be broken?

[peceha]

Hi,
the listing below adds an entry to Exchange program...


But...
the result is shown below

- no name, title, and description is broken
moreover, looks like attached msg port (to the broker) is not getting anything - The program should be terminated whenever a message comes in (e.g. by pressing any of the "command" gadgets in Exchange). .. but it is not...

Is it something wrong in my code or there is a chance that CxBroker_() in Blitz is broken?

Thanks


edit
there is a typo in the listing in the WAIT_(...) line
"cxmax" should read "cxmask"
I fixed that already but still no messages are comming.

[thomas]

CxBroker_ obviously cannot be broken because all that fails are the strings and CxBroker_ does not do anything with the strings. It just takes the pointer to the NewBroker structure and forwards it to the system's CxBroker function.

Apparently your NewBroker structure is not filled in correctly. The nb_Name, nb_Title and nb_Descr fields need to be pointers to characters. So I ask you because I don't know Blitz Basic, is &nb_name$ the right way to get a pointer to where the characters are in the string. For me this looks like nb_name$ is a pointer to the string and &nb_name$ becomes a pointer to a pointer.

The other idea is: how long to strings live in Blitz Basic? Is there something like local variables which disappear when the subroutine exits? The strings in the NewBroker structures are not copied by the system, so they need to stay alive as long as the commodity is living.


Oh, and you don't any messages because you wait for cxmax rather than cxmask. Assuming that uninitialised variables are 0, it won't wait for anything but Ctrl-C.

And even if you get one message, you'll never get another one because you never do ReplyMsg.

[peceha]

Hi,
I've been playing with blitz and system commands for some time already and figured out most of the tricks when passing pointers and so on
So yes, if s$ is a string then &s$ is a pointer to it.
I'm aware about the strings not being copied into the structures so these strings are left untouched trough whole program.

By "broken CxBroker" I meant something wrong inside blitz wraper .

In autodocs I found that nb_Version MUST be set to #NB_VERSION
And since there is an error code if nb_Version is unknown - I tried nb_Version = -99 and a pointer in CxBroker's second argument - hoping for some clues.. but still nothing

That is why I suspect that blitz version of CxBroker_ is not passing broker structure at all.

About a cxmax / cxmask - I fixed that already

Thanks



edit
I just commented out the whole nb structure so it means all its fields are zeroed and started the program - there is only one different: description of the program in Exchange window is now empty...

and just to be sure I passed the strings without & - still the same

[thomas]

You are right, CxBroker seems to succeed even with a NULL pointer for nb.

Maybe the arguments are just swapped. Can you try CxBroker_(0,&nb) ?

[peceha]

That was a good idea but it didn't work either.

And yes, passing NULL pointer to NewBroker structure in CXBroker_() succeeds.
So.. I think... that Blitz implementation of that command is somehow kaput