> For the complete documentation index, see [llms.txt](https://jackx8x7x.gitbook.io/security-stuff/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://jackx8x7x.gitbook.io/security-stuff/windows/execution/api.md).

# Windows APIs

## Win32 API

### History

Prior to 64-bit Windows, the 32-bit Windows API was called the Win32 API to distinguish it from the original 16-bit Windows API in 16-bit versions of Windows.

Originally consisted of C-style functions only.

### Encoding

## Component Object Model (COM)

The lack of naming consistency and logical groupings of the C-style API resulted in these newer APIs.

### Object Linking and Embedding (OLE)

COM initially was called OLE 2 and created to enable Microsoft Office applications to communicate and exchange data between documents.

### Interface

* Well-defined contracts with a set of logically related methods grouped under the *virtual table dispatch mechanism*.
* It is possible to call these methods from many languages

### COM client

Client communicate with object through interfaces.

### COM server

* Dynamic Link Library (DLL) or an executable (EXE) where the COM classes are implemented.
* Thus component implementation can be loaded dynamically rather than being statically linked to the client.

## Windows Runtime

Abbreviated *WinRT*.

### Windows Apps

Formerly known as *Metro Apps*, *Modern Apps*, *Immersive Apps*, and *Windows Store Apps*)

[Windows Internals, Part2 - Management mechanisms](/security-stuff/windows/execution/api.md)

### Model

WinRT is *built on top of COM*, adding various extensions to the base COM infrastructure.

### Application

Applications written in C++, C# (or other .NET languages), and JavaScript can consume WinRT APIs

## .Net Framework

### Implementation

It’s implemented as a COM in-process server (DLL) and uses various facilities provided by the Windows API.

### Common Language Runtime

The *run-time engine* for .NET and includes a *Just In Time (JIT) compiler* that translates Common Intermediate Language (CIL) instructions to

* the underlying hardware CPU machine language
* a garbage collector
* type verification
* code access security.

### .NET Framework Class Library (FCL)

A large collection of types that implement functionality typically needed by client and server applications

## Reference

[Windows Internals, Part 1](https://learning.oreilly.com/library/view/windows-internals-part/9780133986471/ch01.html#ch01lev2sec)\
[Windows App Development - Programming reference for the Win32 API](https://learn.microsoft.com/en-us/windows/win32/api/)