C++ Importing a DLL and using its callback funtions - c++

Question

I have imported a DLL into my program, and there are a few functions as follows:
typedef int (*FEEDQ_CALLBACK) ( long nSD, long nQtype, long nNumber ) ;
typedef int (*CALLDISP_CALLBACK) ( AODFeedDispositionBase* CallDisposition );
typedef int (*SERVICE_STATUS_CALLBACK) ( long nSD, long nStatus ) ;
typedef int (*AUTH_SERVICE_CALLBACK) ( long nSD, char* sSDesc, long nSType ) ;
typedef int (*INBOUND_ABANDON_CALLBACK) ( long nSD, DCCProInboundDisposition* inbounCall ) ;
typedef int (*SESSION_STATUS_CALLBACK) ( long lTypeId, long lStatus ) ;
extern "C"
{
//Methods
AODFEEDAPI short Initialize(const char * sTenantName, const char * sUserID, const char * sPassword, AUTH_SERVICE_CALLBACK pAuthSrvFunc, SERVICE_STATUS_CALLBACK pSrvStatFunc, FEEDQ_CALLBACK pFeedQFunc, CALLDISP_CALLBACK pCallDispFunc, INBOUND_ABANDON_CALLBACK pInboundCallFunc, SESSION_STATUS_CALLBACK pSessionStatFunc = 0);
AODFEEDAPI short Close();
AODFEEDAPI short StopService( long nServiceID, long nQueueAction );
AODFEEDAPI short StartService(long nServiceID);
}
I want to call the Initialize() function in the DLL. I'm confused as to how I should pass the parameters in the callback function.

Answer 1

You don't pass parameters to the callbacks. The callbacks are functions you define in your own code and then give to the DLL so it can call them when needed, passing parameters to you. For example:
int MyFeedQCallback( long nSD, long nQtype, long nNumber )
{
// do something...
}
int MyCallDispCallback( AODFeedDispositionBase* CallDisposition )
{
// do something...
}
int MyServiceStatusCallback( long nSD, long nStatus )
{
// do something...
}
int MyAuthServiceCallback( long nSD, char* sSDesc, long nSType )
{
// do something...
}
int MyInboundAbandonCallback( long nSD, DCCProInboundDisposition* inbounCall )
{
// do something...
}
int MySessionStatusCallback( long lTypeId, long lStatus )
{
// do something...
}
int main()
{
...
short ret = Initialize("tenant name", "user ID", "password", &AuthServiceCallback, &MyServiceStatusCallback, &MyFeedQCallback, &MyCallDispCallback, &MyInboundAbandonCallback, &MySessionStatusCallback);
...
long serviceID = ...;
StartService(serviceID);
...
StopService(serviceID, queueAction);
...
Close();
return 0;
}