I know that Java code is compiled into byte-code, that is executed by the JVM.
What is the case with C# ? I have noticed that applications written in C# have the .exe extension what would suggest they are native machine instructions. but is it really so ?
No.
Like Java, C# is compiled to an intermediary language (called MSIL or CIL).
Unlike Java, the IL is stored in EXE files which have enough actual EXE code to show a dialog box asking users to install .Net.
C# compilation is done in these two steps :
1. Conversion from C# to CIL by the C# compiler
2. Conversion from CIL to instructions that the processor can execute.
A component (just in time) performs this compilation at run time from CIL to machine code
What that .exe is supposed to tell you is that the file is executable. C# is compiled into bytecode, just as java is, but .NET wraps this in a CLR executable.
Look here for a more in depth look at CLR executable http://etutorials.org/Programming/.NET+Framework+Essentials/Chapter+2.+The+Common+Language+Runtime/2.2+CLR+Executables/
c# code is compiled to MSIL. it likes java bytecode. msil will be convert to machine isntrctions at runtime.
C# code is compiled to MSIL, MSIL is taken care by .NET CLR
There is also a project that allows compilation of C# to standalone binary executables: CoreRT
Related
If I run a .NET compiler it produces a file containing intermediate language code (IL) and put it into, an .exe file (for instance).
After if I use a tool like ildasm it shows me the IL code again.
However if I write directly into a file IL code then I can use ilasm to produce an .exe file.
What does it contain? IL code again? Is IL code different to IL assembly code?
Is there a difference between IL code and IL assembly?
Yes, there is a big difference between them, since :
(IL) which is also known as Microsoft Intermediate Language or Common Intermediate Language can be considered very similar to the Byte Code generated by the Java Language, and is what I think you are referring as IL Code in your question .
(ILAsm) has the instruction set same as that the native assembly language has. You can write code for ILAsm in any text editor like notepad and then can use the command line compiler (ILAsm.exe) provided by the .NET framework to compile that.
I think that IL Assembly can be considered a fully fledged .NET language(maybe an intermediate language), so when you compile ILAsm with ILAsm.exe you are producing IL in pretty much the same way(with less steps) that your C# compiler does with C# Code ...
As someone stated in the comment IL Assembly is basically a human readable version of the .NET Byte Code.
A .NET assembly does not contain MSIL, it contains metadata and bytes that represent IL opcodes. Pure binary data, not text. Any .NET decompiler, like ildasm.exe, knows how to convert the bytes back to text. It is pretty straight-forward.
The C# compiler directly generates the binary data, there is no intermediate text format. When you write your own IL code with a text editor then you need ilasm.exe to convert it to binary. It is pretty straight-forward.
The most difficult job of generating the binary data is the metadata btw. It is excessively micro-optimized to make it as small as possible, its structure is quite convoluted. No compiler generates the bytes directly, they'll use a pre-built component to get that job done. Notable is that Roslyn had to rewrite this from scratch, big job.
As the title says I want to load a C++ program into a C# AppDomain using C#.
I cannot use AppDomain.ExecuteAssembly() because it has to be a C# or another non C++ language to use this.
Is it possible to load a C++ programm?
As far as I know AppDomain is a logical region inside a process, in which one or more assemblies can be loaded. That being said, I don't think that this is even feasible.
However, you have the ability you invoke native C++ DLL from a .NET assembly. Here is a helpful link, in which you will some options you have in order to invoke native C++ DLL from a .NET assembly.
side note
I cannot use AppDomain.ExecuteAssembly() because it has to be a C#
program to use this.
This is not true. If you write your program in any .NET language, the compiled version of your code would be an assembly, which will contain the same code and data files. So, AppDomain.ExecuteAssembly() can execute any .net assembly, without this assembly have been created by a C# compiler.
I am just looking into compilers and I was wondering is it possible to compile both c# and c++ files from a Java Application (e.g. to compile java from a java application you can use the JavaCompiler API). I have looked online for this but all i can find is ways to compile java files from c# and c++ and not the other way around.
If so, what API's can you use for this?
If you know the system commands for compiling and executing .cpp files(don't know much about c#) you might want to check out this. It details how to execute system commands from a Java program. Pass the system commands for compiling the required file in Runtime.getRuntime().exec().
Consider learning how to call ant from Java code and using something like this ant enhancement.
Disclaimer: I don't know anything about this product, but found it by searching for "can ant build c++?"
For C# in Windows: compiler (csc.exe) is part of .Net install on Windows and can be found at well known location (like %windir%\Microsoft.NET\Framework\v3.5 for .Net 3.5). The same place also contains MSBuild.exe that can build project files (*.csproj).
Your code may need to provide locations for referenced libraries if using Csc.exe to compile individual files.
I just looked at the source of Mono for the first time and I thought I would find a bunch of C or C++ code, instead I found 26,192 .cs files and 7 .cpp files.
I am not totally shocked but it made me think of a quesiton I've always had in the back of my mind:
How does a project end up being written in "itself" like this?
Was an older version of mono more c/c++? Or was there initial effort to create some kind of machine coded compiler...
What's the "trick" here?
Mono's compiler is written in C#. You may want to read about compiler bootstrapping.
You should be looking for .c files, instead of .cpp files: the mono runtime is written in C, not C++.
I think it is also important to remember that mono is both a virtual machine runtime (the JIT compiler, garbage collector, etc.) as well as a collection of class libraries that run on this framework (the System.Linq namespace, the XML parsers, etc.).
The majority of the .cs files you see are part of the class libraries. These are basically C# code that run like your own C# code (with some exceptions, but basically it doesn't make sense for everyone to reinvent and re-distribute the wheel over and over, so these are the C# "base" class libraries). This is why you can download complex mono programs as such small file sizes if mono is already installed on the machine.
For mono, the JIT, runtime and garbage collector are largely written in C/C++ as you would expect. If you ever get a low level error, you will often see GNU debug tool dumps as you would in C, just with lots more useful information. The Mono framework is very good at taking any C# code and converting it to CIL code that can run anywhere, and they use whatever toolset is best suited to ensure the code does run anywhere (which in this case meant a C compiler runtime on linux).
whats the relation(if any) of MASM assembly language and ILASM. Is there a one to one conversion? Im trying to incorporate Quantum GIS into a program Im kinda writing as I go along! I have GIS on my computer, I have RedGate Reflector and it nor the Object Browser of Visual Studio 2008 couldnt open one(of several which I dont have a strong clue to how they behave) of the .dlls in Quantum. I used the MASM assembly editor and "opened" the same dll and it spewed something I didnt expect to necessarily understand in the first place. How can I/can I make a conversion of that same "code" to something I can interact with in ILASM and Im assuming consequently in Csharp? Thanks a ton for reading and all the responses to earlier questions...please bear in mind Im relatively new to programming in Csharp, and even fresher to MASM and ILASM.
MASM deals with the x86 instructions and is platform/processor dependent, while ILASM reffers to the .Net CIL (common intermediary language) instructions which are platform/processor independent. Switching from something specific to something more general is hard to achieve, that's why, AFAIK, there is no converter from MASM to ILASM (inverse, there is!)
IL is a platform independent layer of abstraction over native code. Code written on the .NET platform in C#, VB.NET, or other .NET language all compile down to an assembly .EXE/.DLL containing IL. Typically, the first time the IL code is executed the .NET runtime will run it through NGen, which compiles it once again down to native code and stores the output in a temporary location where it is actually executed. This allows .NET platform code to be deployed to any platform supporting that .NET framework, regardless of the processor or architecture of the system.
As you've seen, Reflector is great for viewing the code in an assembly because IL can easily be previewed in C# or VB.NET form. This is because IL is generally a little higher level instructions and also contain a lot of metadata that native code wouldn't normally have, such as class, method, and variable names.
It's also possible to compile a .NET project directly to native code by setting the Visual Studio project platform or by calling Ngen.exe directly on the assembly. Once done, it's really difficult to make sense of the native code.
Ther is no relationship between MASM assembly language and ILASM. I don't see you have any way to convert native code to IL code. IL can be understood by CLR only while the MASM assembly language is about native machine code. CLR turns the IL into native code in runtime