Calling a DLL Function

Although calling unmanaged DLL functions is nearly identical to calling other managed code, there are differences that can make DLL functions seem confusing at first. This section introduces topics that describe some of the unusual calling-related issues.

Structures that are returned from platform invoke calls must be data types that have the same representation in managed and unmanaged code. Such types are called blittable types because they do not require conversion (see Blittable and Non-Blittable Types). To call a function that has a non-blittable structure as its return type, you can define a blittable helper type of the same size as the non-blittable type and convert the data after the function returns.

In This Section

Passing Structures
Identifies the issues of passing data structures with a predefined layout.

Callback Functions
Provides basic information about callback functions.

How to: Implement Callback Functions
Describes how to implement callback functions in managed code.

Related Sections

Consuming Unmanaged DLL Functions
Describes how to call unmanaged DLL functions using platform invoke.

Marshalling Data with Platform Invoke
Describes how to declare method parameters and pass arguments to functions exported by unmanaged libraries.