instantiation

I'm currently dealing with Windows Media Foundation. However, due to some problems with the Microsoft H.264 decoder and some missing decoders for custom format, I'd like to know if it would be possible to instantiate a DirectShow Decoder directly using CLSID, and build a proxy around it that exposes IMFTransform to get a decoder for Media Foundation. So here is my question: Can i instantiate a Directshow filter (preferrably decoders) directly and use them for decoding (i.e. put some compressed frames and get uncompressed ones) to create a MFT? I know how to instantiate the filter itself using

In R6, How can I get the full list of class inheritances, without creating instances of the generator objects? Consider the following: A = R6::R6Class("Base",NULL) B = R6::R6Class("Top",inherit = A) class(B) #Returns 'R6ClassGenerator' B$classname #Returns 'Top' What I want is c('Top','Base','R6') In other words, what would otherwise be returned by class(B$new()) In the real world, I have a complex set of inheritances, and, initializers with many arguments, some without default values, so I am trying to avoid instantiating a new object in order to obtain this information. There isn't a built

Let's say I have some class - hypothetical example: public class InvalidResponseException<TReq, TResp> : Exception { public TReq RequestData { get; protected set; } public TResp ResponseData { get; protected set; } public InvalidResponseException(string message, TReq requestData, TResp responseData) : this(message, null, requestData, responseData) { } public InvalidResponseException(string message, Exception innerException, TReq requestData, TResp responseData) : base(message, innerException) { RequestData = requestData; ResponseData = responseData; } } Okay, class defined... and compiles, no

In my Android application, I have a fragment activity which it has a progressbar. This progress bar set to visible when any fragment invoke the interface. Therefore, the code for fragment class is like this: public class MainScreen extends FragmentActivity { public interface OnConnectingToInternet { public void showProgressbar(boolean flag); } // rest of codes . . . // Implementing Interface public void showProgressbar(boolean flag) { if(flag){ myProgressbar.showProgressBar(); } else { myProgressbar.hideProgressBar(); } } } Each fragment should connect to Internet and get data, however before

It is my understanding that either a declaration or typedef of a specialization ought to cause a template class to be instantiated, but this does not appear to be happening with gcc. E.g. I have a template class, template class Foo {}; I write class Foo<double>; or typedef Foo<double> DoubleFoo; but after compilation the symbol table of the resulting object file does not contain the members of Foo. If I create an instance : Foo<double> aFoo; then of course the symbols are all generated. Has anyone else experienced this and/or have an explanation? The syntax for explicit instantiation is

Is there a way to stop a C++ class if there is an error in the instantiation? Like, return NULL maybe? Basically I have a wrapper class for MySQL, and the constructor does the connecting, but if the connection fails, I want the object to be, um, useless? PDB::PDB(string _DB_IP, string _DB_USER, string _DB_PASS, string _DB_DB) : _DB_IP( _DB_IP ), _DB_USER( _DB_USER ), _DB_PASS( _DB_PASS ), _DB_DB( _DB_DB ) { mysql_init(&this->mysql); this->connection = mysql_real_connect(&this->mysql, this->_DB_IP.c_str(), this->_DB_USER.c_str(), this->_DB_PASS.c_str(), this->_DB_DB.c_str(), 0, 0, 0); if( this-