The /J compiler switch is incompatible with ATL and MFC applications (813540)


The information in this article applies to:

  • Microsoft Visual C++ 2005 Express Edition
  • Microsoft Visual C++ .NET (2003)
  • Microsoft Visual C++ .NET (2002)

SUMMARY

By default, the Microsoft C compiler or the Microsoft C++ compiler (cl.exe) sets the char type to a signed char data type. You can use the /J compiler switch that sets the char type to unsigned char . However, the /J compiler switch is incompatible with Active Template Library (ATL) applications and Microsoft Foundation Class (MFC) applications. If the /J command line switch is added while compiling MFC or ATL applications, you may not see any compiler error or warning. However, unintended side effects, such as data loss, may occur at runtime.

MORE INFORMATION

This switch was not designed to be used with ATL and MFC applications. MFC and ATL libraries are built and tested with a char type that is defined as a signed int data type.

REFERENCES

For more information about the /J compiler switch, visit the following Microsoft Developer Network (MSDN) Web site:

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vccore/html/_core_.2f.j.asp

Modification Type:MajorLast Reviewed:1/12/2006
Keywords:kbCompiler kbinfo KB813540 kbAudDeveloper
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