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.
/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
- In Solution Explorer, open the shortcut menu for the project and then choose Properties. 
- In the project Property Pages dialog box, in the left pane under Configuration Properties, expand C/C++ and then select Command Line. 
- In the Additional Options pane, specify the /J compiler option. 
To set this compiler option programmatically
See Also
Tasks
How to: Open Project Property Pages