Microsoft KB Archive/65306

= INFO: toupper Generates C4135 or C4244 Warning =

Q65306

-

The information in this article applies to:


 * The C Run-time,
 * Microsoft C for MS-DOS, versions 6.0, 6.0a, 6.0ax
 * Microsoft C/C++ for MS-DOS, version 7.0
 * Microsoft Visual C++ for Windows, 16-bit edition, versions 1.0, 1.5
 * Microsoft Visual C++, 32-bit Editions, versions 1.0, 2.0, 2.1, 4.0, 5.0, 6.0

-

When compiling a function that contains a call to toupper in the following format:   char toupper (char) at warning level 4, the compiler will generate the following warning message:

C4135: Conversion between two integral types

With Visual C++ version 4.0, the compiler will generate the following warning message:

warning C4244: ' ' : conversion from 'int ' to 'char ', possible loss of data

Because the ANSI-standard draft of December 7, 1988, specifies the syntax for this function as follows, the warning is in compliance with the standard:   int toupper (int) The error can be resolved by casting the return value. For example:   char a, b;     a = (char)toupper(b); Additional query words:

Keywords : kberrmsg kbCRT kbVC100 kbVC150 kbVC200 kbVC210 kbVC400 kbVC500 kbVC600

Issue type : kbinfo

Technology :

Last Reviewed: September 4, 2001

-

[mailto:MSDN@MICROSOFT.COM Send feedback to Microsoft]

© 2002 Microsoft Corporation. All rights reserved.