---
description: "Learn more about: Compiler COM Support"
title: "Compiler COM Support"
ms.date: "05/06/2019"
helpviewer_keywords: ["cl.exe compiler, COM support", "COM, compiler support"]
ms.assetid: 76a78442-f2a4-4985-9967-67e20773f847
---
# Compiler COM Support

**Microsoft Specific**

The Microsoft C++ compiler can directly read component object model (COM) type libraries and translate the contents into C++ source code that can be included in the compilation. Language extensions are available to facilitate COM programming on the client side for desktop apps.

By using the [#import preprocessor directive](../preprocessor/hash-import-directive-cpp.md), the compiler can read a type library and convert it into a C++ header file that describes the COM interfaces as classes. A set of `#import` attributes is available for user control of the content for the resulting type library header files.

You can use the [__declspec](../cpp/declspec.md) extended attribute [uuid](../cpp/uuid-cpp.md) to assign a globally unique identifier (GUID) to a COM object. The keyword [__uuidof](../cpp/uuidof-operator.md) can be used to extract the GUID associated with a COM object. Another **`__declspec`** attribute, [property](../cpp/property-cpp.md), can be used to specify the `get` and `set` methods for a data member of a COM object.

A set of COM support global functions and classes is provided to support the `VARIANT` and `BSTR` types, implement smart pointers, and encapsulate the error object thrown by `_com_raise_error`:

- [Compiler COM Global Functions](../cpp/compiler-com-global-functions.md)

- [_bstr_t](../cpp/bstr-t-class.md)

- [_com_error](../cpp/com-error-class.md)

- [_com_ptr_t](../cpp/com-ptr-t-class.md)

- [_variant_t](../cpp/variant-t-class.md)

**END Microsoft Specific**

## See also

[Compiler COM Support Classes](../cpp/compiler-com-support-classes.md)<br/>
[Compiler COM Global Functions](../cpp/compiler-com-global-functions.md)