onUpdateClientEvent crashes Client

[Schuwi]

Hello,

I am developing a plugin in C++ using the Teamspeak PluginSDK. I want to use the onUpdateClientEvent to react to a user changing its username and it works just fine but when I kick a client (whether with the SDK or manually using the GUI) my client crashes with this error in log:

2015-09-01 15:50:00.104221|CRITICAL|              |   |Assertion "item->getChildCount() == 0" failed at c:\jenkins\workspace\clientwindows_gyp\src\ui_qt\treemodel.cpp:580;

I am using the following code for testing:

void logmsg(string msg) {
    ts3Functions.logMessage(msg.c_str(), LogLevel_DEBUG, "TestPlugin", 0);
}

void ts3plugin_onUpdateClientEvent(UINT64 scHandlerID, anyID clientID, anyID invokerID, const char *invokerName, const char *invokerUniqueIdentifier) {
    logmsg("updateClient" + to_string(scHandlerID) + ";" + to_string(clientID) + ";" + to_string(invokerID));
    anyID* selfID;
    ts3Functions.getClientID(scHandlerID, selfID);
    logmsg("selfID=" + to_string(*selfID) + ";clientID=" + to_string(clientID) + ";invokerID=" + to_string(invokerID));
}

The weird thing is that its not even printing the first log message even though its called before the getClientID but the crash is definitly caused by the getClientID call because when removing the getClientID call it does not crash.


I hope somebody can help me
Thanks in advance

Schuwi

[Philosound]

Let's see if that changes anything.

unsigned int error;
anyID selfID;
if((error = ts3Functions.getClientID(scHandlerID,&selfID)) != ERROR_ok)
{ logmsg("nay"); } else {
logmsg("selfID=" + to_string(selfID) + ";clientID=" + to_string(clientID) + ";invokerID=" + to_string(invokerID)); //yay }

I guess the client uses asynchronous Qt-based logging. We don't wanna slow down our function execution by waiting for logs to be written, do we

Edith: However from the error message and the kick requirement I'd have bet the clientID to cause havoc. After all, we're for some reason handling an event for a client that may or may not exist at all anymore (channel/server kick?). But given that you just print it, I dunno.

[Chris]

You're asking the client to write data to an uninitialized variable, this variable being a pointer for which no memory has been allocated. You either have to allocate (and de-allocate) it explicitly

anyID *selfID = (anyID*) malloc(sizeof(anyID));
ts3Functions.getClientID(scHandlerID, selfID);
// use selfID
free(selfID);

or use local variables and provide the function call with a pointer to that variable like Philosound does in his answer.

anyID selfID;
ts3Functions.getClientID(scHandlerID, &selfID);

With your code you may end up overwriting some random memory to which you have access to and that isn't needed anymore (no crash) or you overwrite stuff that's still needed or even some memory you don't have access to (crash in both cases).

[Schuwi]

Ok I see... I'm very new to C and was only into Java before.
I already worked around the issue with using onClientDisplayNameChanged(saw that a bit late...) but I fixed that with the pointer, looks like I was lucky not overwriting something when using onClientDisplayNameChanged.
Thank you very much for your help

Schuwi

P.S.: Is there any function to schedule a repetitive task or should I just do it in a thread?