At times, it is necessary to use native codes (C/C++) to overcome the memory management and performance constraints in Java. Java supports native codes. 159 thoughts on “ Using C# from native C++ with the help of C++/CLI (fixed and enhanced) ”. This article briefly explains what a native Windows Dynamic Link Library (DLL) is, shows how to create a DLL using C++, how to consume it in C# and then explains how. Compiling Apps with . NET Native. NET Native is a precompilation technology for building and deploying Windows apps that is included with Visual Studio 2. It automatically compiles the release version of apps that are written in managed code (C# or Visual Basic) and that target the . NET Framework and Windows 1. Typically, apps that target the . NET Framework are compiled to intermediate language (IL). At run time, the just- in- time (JIT) compiler translates the IL to native code. In my previous article, I gave a short introduction into some Anti-Debugging/Debugger Detection techniques that primarily involved the use of Win32 API functions.The Windows API, informally WinAPI, is Microsoft's core set of application programming interfaces (APIs) available in the Microsoft Windows operating systems. In contrast, . NET Native compiles Windows apps directly to native code. For developers, this means: Your apps will provide the superior performance of native code. You can continue to program in C# or Visual Basic. You can continue to take advantage of the resources provided by the . NET Framework, including its class library, automatic memory management and garbage collection, and exception handling. For users of your apps, . NET Native offers these advantages: Fast execution times Consistently speedy startup times Low deployment and update costs Optimized app memory usage But . NET Native involves more than a compilation to native code. It transforms the way that . NET Framework apps are built and executed. It is recommended new project should migrate to libusb-1.0 API and use libusb Windows (http. In particular: During precompilation, required portions of the . NET Framework are statically linked into your app. This allows the app to run with app- local libraries of the . NET Framework, and the compiler to perform global analysis to deliver performance wins. As a result, apps launch consistently faster even after . NET Framework updates. The . NET Native runtime is optimized for static precompilation and thus is able to offer superior performance. At the same time, it retains the core reflection features that developers find so productive. Java Native Interface - Wikipedia, the free encyclopedia. In computing, the Java Native Interface (JNI) is a programming framework that enables Java code running in a Java Virtual Machine (JVM) to call and be called by. It is also used to modify an existing application. Many of the standard library classes depend on JNI to provide functionality to the developer and the user, e. Including performance- and platform- sensitive API implementations in the standard library allows all Java applications to access this functionality in a safe and platform- independent manner. The JNI framework lets a native method use Java objects in the same way that Java code uses these objects. A native method can create Java objects and then inspect and use these objects to perform its tasks. A native method can also inspect and use objects created by Java application code. Pitfalls. Consequently, native side code (such as assembly language) assumes the responsibility for explicitly releasing any such memory resources that the native code acquires. On Linux and Solaris platforms, if the native code registers itself as a signal handler, it could intercept signals intended for the JVM. A chain of responsibility can be used to allow native code to better inter- operate with the JVM. On Windows platforms, Structured Exception Handling (SEH) may be employed to wrap native code in SEH try/catch blocks so as to capture machine (CPU/FPU) generated software interrupts (such as NULL pointer access violations and divide- by- zero operations), and to handle these situations before the interrupt is propagated back up into the JVM (i. Java side code), in all likelihood resulting in an unhandled exception. The encoding used for the New. String. UTF, Get. String. UTFLength, Get. String. UTFChars, Release. String. UTFChars and Get. String. UTFRegion functions is . The null character (U+0. Basic Multilingual Plane (greater than or equal to U+1. Many programs actually use these functions incorrectly and treat the UTF- 8 strings returned or passed into the functions as standard UTF- 8 strings instead of modified UTF- 8 strings. Programs should use the New. String, Get. String. Length, Get. String. Chars, Release. String. Chars, Get. String. Region, Get. String. Critical and Release. String. Critical functions, which use UTF- 1. LE encoding on little- endian architectures and UTF- 1. BE on big- endian architectures, and then use a UTF- 1. UTF- 8 conversion routine. JNI incurs considerable overhead and performance loss under certain circumstances. The cost can be linear in the size of the array. If the method is passed an object, or needs to make a callback, then the native method will likely be making its own calls to the JVM. Accessing Java fields, methods and types from the native code requires something similar to reflection. Signatures are specified in strings and queried from the JVM. This is both slow and error- prone. Java Strings are objects, have length and are encoded. Accessing or creating a string may require an O(n) copy. How the JNI works. A JNI function may look like this: JNIEXPORTvoid. JNICALLJava. It includes all of the functions necessary to interact with the JVM and to work with Java objects. Example JNI functions are converting native arrays to/from Java arrays, converting native strings to/from Java strings, instantiating objects, throwing exceptions, etc. Basically, anything that Java code can do can be done using JNIEnv, albeit with considerably less ease. The argument obj is a reference to the Java object inside which this native method has been declared. For example, the following converts a Java string to a native string: //C++ codeextern. For compound types such as objects, arrays and strings the native code must explicitly convert the data by calling methods in the JNIEnv. Mapping types. Finally, a void signature uses the V code. Here, these types are interchangeable. You can use jint where you normally use an int, and vice versa, without any typecasting required. However, mapping between Java Strings and arrays to native strings and arrays is different. If you use a jstring in where a char * would be, your code could crash the JVM./*C code*/JNIEXPORTvoid. JNICALLJava. Look for links below for more information. JNIEnv*. This JNI interface pointer can be stored, but remains valid only in the current thread. Other threads must first call Attach. Current. Thread() to attach themselves to the VM and obtain a JNI interface pointer. Once attached, a native thread works like a regular Java thread running within a native method. The native thread remains attached to the VM until it calls Detach. Current. Thread() to detach itself. The process is almost the same, with just a few changes. The Java AWT Native Interface is only available since J2. SE 1. 3. Access to assembly code. In addition, it has an easy way to call existing native code that isn't itself aware of Java, such as (but not limited to) the Windows API, called J/Direct. However, following the Sun - Microsoft litigation about this implementation, Visual J++ is no longer maintained. RNI was less clumsy to use than JNI, because no bookkeeping with a Java environment pointer was needed. Instead, all Java objects could be accessed directly. To facilitate this, a tool was used that generated header files from Java classes. Similarly, J/Direct was easier to use than using the necessary intermediate native library and JNI, although at present JNA is an alternative. Examples. Java Class methods and fields (which are represented as . NET Class properties) to be wrapped can be filtered.
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