I'm trying to make something in C# that requires calling into some unmanaged DLLs, a process which I know nothing about! I found a "Hello World" tutorial that should be as simple as copying and pasting a couple lines of code from the bottom:
using System;
using System.Runtime.InteropServices;
namespace PInvokeTest
{
class Program
{
[DllImport("msvcrt40.dll")]
public static extern int printf(string format, __arglist);
public static void Main()
{
printf("Hello %s!\n", __arglist("World"));
Console.ReadKey();
}
}
}
This compiles and runs to completion without any errors, however nothing is printed by the time it gets to the ReadKey().
Did I miss some important setup step? The project builds for .NET 4.6.1 (in case that matters for DLL versioning or something).
The version of msvcrt* you are using is likely the problem. If I create a console app with your unmodified code, I get the same result -- no output.
If I change the referenced dll from msvcrt40.dll to msvcr120.dll then I see the expected output.
[DllImport("msvcr120.dll")]
public static extern int printf(string format, __arglist);
public static void Main()
{
printf("Hello %s!\n", __arglist("World"));
Console.ReadKey();
}
The various numbered versions of msvcrt* track the versions of Visual Studio:
This version numbering approach has changed in VS2015 due to the confusion and brittle dependency-chains this creates. More information about these changes can be found here: