How can I use C# code from a C++ DLL [closed] - c#

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I have a requirement that dictates use of an exported function from a C++ dll.
There is lots of stuff that needs to occur within the exported function, but I don't want to rewrite all of the C# code that I have written to do it.
I would like to just paste the C# code into the DLL and be done.
NOTE: I don't want to call a C# DLL, I want to put C# code INTO a C++ dll.
Here is the Exports.def file:
LIBRARY InstallCheckWin32
EXPORTS
IsConnectionPointValid #1
fnTest #2
Here is my .h File for the DLL:
// The following ifdef block is the standard way of creating macros which make exporting
// from a DLL simpler. All files within this DLL are compiled with the INSTALLCHECKWIN32_EXPORTS
// symbol defined on the command line. This symbol should not be defined on any project
// that uses this DLL. This way any other project whose source files include this file see
// INSTALLCHECKWIN32_API functions as being imported from a DLL, whereas this DLL sees symbols
// defined with this macro as being exported.
#ifdef INSTALLCHECKWIN32_EXPORTS
#define INSTALLCHECKWIN32_API __declspec(dllexport)
#else
#define INSTALLCHECKWIN32_API __declspec(dllimport)
#endif
INSTALLCHECKWIN32_API void CallCSharp();
Here is the .cpp file:
// InstallCheckWin32.cpp : Defines the exported functions for the DLL application.
//
#include "stdafx.h"
#include "InstallCheckWin32.h"
#include <tchar.h>
INSTALLCHECKWIN32_API void CallCSharp()
{
// this is where I want to use C# objects
// eg:
DateTime now = DateTime.Now;
}
I have set the General Configuration Property "Common Language Runtime Support" to Common Language Runtime Support(/clr)
What else do I need to set to use C# code in a C++ dll?
Thanks

No, you can't mix C# and C/C++ in same source file and expect compiler to somehow produce code for that.
In general mixing multiple coding languages in the same file has only limited support in some languages. With C/C++ you sometimes can mix assembly (as in mov ax,cx, not .Net assembly). Language/frameworks for site creation you frequently can mix in JavaScript (but not actually run at the same time)...
Fix: in most cases languages have comparable functionality/libraries - so it is frequently easier to rewrite code into one of the language. You can also interop between libraries written in different languages - how to do that depends on combination of languages. For some cases you can cross-compile source in one language to another, but generally it is limited to languages with same/similar frameworks (C++/C# is generally not falling into such bucket, but you still may find C# to C++ cross-compiler)

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How to disassemble .NET code right? [closed]

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I'm trying to disassemble my C# code and then debug it on assembly language level.
Let's say we have a simple C# method:
var a = 1235;
var b = ++a;
var c = ++b;
Console.WriteLine("test");
Console.ReadKey();
I've found two different ways how to get an assembly code.
The first one is to start C# code debugging in VS and then open Disassembly window. Here we have the following code.
Everything is OK and assembly code is pretty much simple and short but the problem is that the logic of this assembly code differs from the logic of the IL code generated by ildasm.
So here is the second way. We can compile C# code, use ildasm to get the IL code from PE file and then use ilasm to generate PE file back. Now we have the following assembly code.
As you can see this assembly code is more like the IL code but it contains much more instructions and it is more complicated.
AFAIK C# compiles to CIL code and then to an assembly code in both cases. But it seems to be that in the first way it just compiles to an assembly code.
So the question is why the assembly code of the first method differs from the IL code? And why the assembly code of the first method differs from the assembly code of the second method?
The JIT is able to re-order and merge machine instructions as an optomisation, but will try to avoid moving the effects across sequence points provided by the pdb. The compiler generally generates one sequence point per line of code, since you generally step through it one line at a time.
While C# will often generate multiple IL instructions per line of code, ilasm is given each instruction explicitly and so generates more sequence points, leaving less room for JIT optimizations.

C# VS 2013 how to call programs in DLL [closed]

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I have a Delphi created DLL that has functions I need to call from VS 2013 C3 app.
Not exactly sure how or where to start to accomplish this.
Do I have to include the dll as a reference or import it somehow or both?
And how do I call the program?
The dll is MSA.dll and the method I need to call looks like this:
GetXML(txtPath.Text, txtCabFile.Text, False);
Any 101 basic suggestion appreciated.
Check out something called "P/Invoke." It allows you to call into "native" (i.e. Delphi, C, etc.) DLLs using simple "extern" function definitions.
Here's a website I use as a resource for P/Invoke calls to the Windows API:
http://www.pinvoke.net/
EDIT: Make sure your target on the .NET side is the same as the one you compiled your Delphi library in. When in doubt, its probably x86 if you're on a PC. Thanks to the commenter below who brought this point to my attention. Don't use AnyCPU.
EDIT 2: The extern declaration you would use:
[DllImport("MSA.dll", CharSet = Ansi)]
public extern string GetXML(string firstParam, string secondParam, bool thirdParam);
You can name the parameters whatever you want. I didn't know what to call them so I just gave them names.

Emitting IronPython code in C# [closed]

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Basically I have two questions:
1) How to emit or generate a IronPython code (tools, libs) in a C# application. The result of this process should be string consisting of real IronPython code not IL code.
2) How beneficial is the approach above over generating a IronPython code on your own (simply by using StringBuilder)?
I am looking for some code generator library similar to this IMAGINARY pseudo code generator:
IronPythonCodeGenerator generator = new IronPythonCodeGenerator();
Parameter param = new Parameter("str");
ParameterValue value=new ParameterValue(param,"This piece is printed by the generated code!!!");
Function function = IronPythonCodeGenerator.CreateFunction("PrintExtended",param);
function.AppendStatement("print",param);
function.AppendStatement(Statements.Return);
FunctionCall functionCall = new FunctionCall(function,value);
generator.MainBody.Append(function);
generator.MainBody.Append(functionCall);
Console.WriteLine(generator.MainBody.ToString());
, which outputs the IronPython code:
def PrintExtended( str ):
print str;
return;
PrintExtended("This piece is printed by the generated code!!!");
Reflection.Emit is for generating IL code, not for generating high-level language code. So if your target language is IronPython, building it up in a StringBuilder is probably your best bet.
It of course depends on your needs. If all you want to do is just generate code without wanting to change the order of methods, or modify methods after they've been defined etc., just constructing code in a StringBuilder and then compiling it would be the easiest way.

Use non-managed code (C) in c# [closed]

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I'm working on a project that combines a very large open source project (OSP) written in C and attempting to build a front end in C#. I'm currently compiling the OSP with Visual Studio 2012 Express and generating all the .exe's, .dll's,etc from this project.
How should I perform the integration? (Remember I have full access to the .h/.c files) I attempted using the IJW (It Just Works) method, but it didn't appear to allow me to import the references for my freshly compiled .dll's. Apart from that, I'm not sure how to execute the various functions within C# (apart from sending command line commands to the .exe's, which I would prefer not to do....)
Do I need to compile the OSP with special options/parameters for IJW, or would it require code rewrite?
For DLL written in C, you need to write the equivalent declarations in C# instead of adding reference to that DLL.
This is called PInvoke.
class ABC
{
[DllImport("abc.dll")]
public static extern int FuncX(int x, int y);
}

Why Compilation Speed Differs a lot in C++ and C#? [duplicate]

This question already has answers here:
Closed 11 years ago.
Possible Duplicate:
Why does C++ compilation take so long?
Coming from C# background, I can't help but notice that the speed of compilation for C++ and C# code differs a lot-- C# is very fast to compile, but C++ is comparatively slow-- very slow, in fact.
Why is this so?
Two big reasons:
C++ has to go and #include and parse all the header files (which means reading text files and interpreting them -- including templates -- and then expanding them right into your code) whereas C# uses pre-compiled information in the assembly DLLs.
The potential C++ optimizations are way more far-reaching than the C# optimizations; they easily blow C# out of the water. The C# compiler never inlines a function call (that's the Just-In-Time compiler's job to do in the CLR), but C++ compilers frequently do that, and much more. The C++ compiler also has to do the JIT's compiler for the entire program at compile time (and then some!), so it's definitely slower.
I'd say that the biggest culprit is optimizations -- try turning off all optimizations in your compiler, and noticing the speedup.

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