C++/CLI: Transformar un String a BSTR u otras cochinadas

Esto es muy común cuando uno quiere reemplazar una interfaz COM por una C++/CLI. Esto típicamente requiere convertir System::String^ a BSTR, std::string y otras yerbas. Por suerte, .NET nos provee una solución que nos evita andar copiando cosas a buffers y viendo cuándo las liberamos: El método marshal_as y la clase marshal_context.

Acá está el detalle de qué usar para cada conversión: Overview of Marshalling in C++

Comments

Post a Comment

Popular posts from this blog

VB.NET: Raise base class events from a derived class

Spanish version / Versión en Español Say we: Have a class we want to divide into subclasses The future base class has events The refactoring leads us to the need of raising an event declared in the base class, from a derived class. When we try to do point 3, we will get a compile error saying that a derived class cannot raise events from a base class. To get around this, we add a protected method in the base class which encapsulates the RaiseEvent call, and call that method from the derived class using MyBase. This way: In the base class (parameters as needed): Protected Overridable Sub OnMessageGenerated(ByVal NewSender As Object, ByVal NewMessage As String) RaiseEvent MessageGenerated(NewSender, New MessageEventArgs(NewMessage)) End Sub And in the derived class: 'Do stuff 'Raise base class event MyBase.OnMessageGenerated( Me, "Message" ) 'Do more stuff... References: Mark Gilbert post
Keep reading

Apache Kafka - I - High level architecture and concepts

Image
Spanish version / Versión en Español First of all, what is Apache Kafka ? An initial definition for it is "a high-throughput distributed messaging system". Breaking this down a bit: High throughput: One of the main goals of Kafka is to process as much messages per unit of time as possible, in a scalable and fault-tolerant way. For example, LinkedIn , which is where Kafka originated, needs to achieve throughputs in the order of 20 million messages per second and 3 GB of data per second. Distributed messaging system: In a generic distributed system , networked computers work together for a common goal. In Kafka's case, that goal is to send data from points A 1 , A 2 , ... A N , to B 1 , B 2 , ... B M . A common benefit of this kind of system, which is crucial to Kafka's success, is horizontal scalability : the ability to handle higher and higher volumes of data by adding nodes to the system (not to be confused with  vertical scalability , whic
Keep reading

C++/CLI: Convert a String to BSTR or some other nasty stuff

Spanish version / Versión en Español This is very usual when replacing a COM interface with a C++/CLI wrapper (Guess who's doing that?). That usually leads to the need to convert a .NET string (System::String^) to a BSTR, or a std::string. Luckily, .NET provides some handy conversion functions for this. They save us the hassle of creating buffers, releasing them and whatnot. Among them are the marshal_as functions and the marshal_context class. Here's the lowdown for when to use which: Overview of Marshalling in C++
Keep reading