j-default-char-type-is-unsigned.md

description	Learn more about: /J (Default char Type Is unsigned)
title	/J (Default char Type Is unsigned)
ms.date	11/04/2016
f1_keywords	VC.Project.VCCLCompilerTool.DefaultCharIsUnsigned VC.Project.VCCLWCECompilerTool.DefaultCharIsUnsigned /j
helpviewer_keywords	defaults, char type char data type -J compiler option [C++] /J compiler option [C++] J compiler option [C++] default char type is unsigned
ms.assetid	50973667-6638-491e-9c41-bff73acae19f

/J (Default char Type Is unsigned)

Changes the default char type from signed char to unsigned char, and the char type is zero-extended when it is widened to an int type.

Syntax

/J

Remarks

If a char value is explicitly declared as signed, the /J option does not affect it, and the value is sign-extended when it is widened to an int type.

The /J option defines _CHAR_UNSIGNED, which is used with #ifndef in the LIMITS.h file to define the range of the default char type.

ANSI C and C++ do not require a specific implementation of the char type. This option is useful when you are working with character data that will eventually be translated into a language other than English.

Note

If you use this compiler option with ATL/MFC, an error might be generated. Although you could disable this error by defining _ATL_ALLOW_CHAR_UNSIGNED, this workaround is not supported and may not always work.

To set this compiler option in the Visual Studio development environment

1. In Solution Explorer, open the shortcut menu for the project and then choose Properties.

2. In the project Property Pages dialog box, in the left pane under Configuration Properties, expand C/C++ and then select Command Line.

3. In the Additional Options pane, specify the /J compiler option.

To set this compiler option programmatically

• See xref:Microsoft.VisualStudio.VCProjectEngine.VCCLCompilerTool.DefaultCharIsUnsigned%2A.

See also

MSVC Compiler Options
MSVC Compiler Command-Line Syntax
Set C++ compiler and build properties in Visual Studio