C# - How can I specify a [DllImport] path at runtime? C# - Why are Cdecl calls often mismatched in the "standard" P/Invoke Convention? .NET Column: Calling Win32 DLLs in C# with P/Invoke. Calling Win32 DLLs in C# with P/Invoke Jason Clark Code download available at:NET0307.exe(133 KB) I have noticed a trend in my programming of late, and that trend has inspired the topic of this month's column. Recently, I have done a fair amount of Win32® Interop in my Microsoft® .NET Framework-based apps. As I think about it, any feature limitation in the .NET Framework version 1.0 or 1.1 class library that is not shared by Windows doesn't come as a huge surprise. As an increasing developer base moves its production applications to managed code, it seems only natural that there will be even more occasions for developers to dip down into the underlying operating system for some critical tidbit of functionality—at least for the time being.
Thankfully, the interop features of the common language run-time (CLR), called Platform Invoke (P/Invoke), are very complete. Enter P/Invoke I'll start by looking at a simple P/Invoke example. BOOL MessageBeep( UINT uType // beep type ); Style Right. DllExports - Common Problems and Solutions. Introduction There are numerous guides on how to export functions from DLLs, but somehow when you start doing DLLs yourself, you run into problems. If you create a DLL in one language and want to use it from another, there are some pitfalls to be aware of.
We will look at some of them. The key to solving problems is really understanding what is going on. I am going to naively start with a simple C++ DLL, and try to lead us into some of the most common problems, Then we will make modifications to the DLL to remedy the problems. Background Sooner or later, you will find the need to use a DLL with exported functions. Let's go back a few years. VB6 was quite slow, and lacked elementary things like unsigned integers and bit shifting, and I think without being able to use DLLs made in other languages, VB6 would never have had as much success as it did. When speed really was needed someone just made a DLL in C or C++, or in any other language. How could VB6 call C++ DLLs? Set the type to "DLL": Pinvoke.net: the interop wiki!