title	Executing a Program in Preprocessing | Microsoft Docs
ms.custom
ms.date	11/04/2016
ms.technology	cpp-tools
ms.topic	conceptual
dev_langs	C++
helpviewer_keywords	program execution [C++]
ms.assetid	5ecf123a-20e5-40cd-b8d8-dd5a9fdd4b24
author	corob-msft
ms.author	corob
ms.workload	cplusplus

Executing a Program in Preprocessing

To use a command's exit code during preprocessing, specify the command, with any arguments, within brackets ([ ]). Any macros are expanded before the command is executed. NMAKE replaces the command specification with the command's exit code, which can be used in an expression to control preprocessing.

See Also

Expressions in Makefile Preprocessing