Q150380: PRB: Sizeof Constant Character Returns Different Values

Article: Q150380
Product(s): Microsoft C Compiler
Version(s): 4.0,4.1
Operating System(s): 
Keyword(s): kbCompiler kbCRT kbVC kbprb
Last Modified: 05-DEC-2001

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The information in this article applies to:

- Microsoft Visual C++, 32-bit Professional Edition, versions 4.0, 4.1 
- Microsoft Visual C++, 32-bit Learning Edition, version 4.0 
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SYMPTOMS
========

The sizeof('x') or sizeof(L'x') constants do not return expected results. In C,
the return value is 4 for the sizeof character constant and 2 for the sizeof
multicharacter constant. In C++, the return value is 1 for the sizeof character
constant and 2 for the sizeof multicharacter constant.

CAUSE
=====

The specification on this point is different for C from what it is for C++. In
C, a character constant is of type int. In C++, a character constant is of type
char. Multicharacter constants are implementation dependent.

RESOLUTION
==========

When using C, do not use sizeof to determine the width of a character constant.
Use sizeof("") to give the width of one character in both C and C++.

STATUS
======

This behavior is by design.

REFERENCES
==========

For more information, see "The Annotated C++ Reference Manual" by Margaret Ellis
and Bjarne Stroustrup, Section 2.5.2.

Additional query words: 2.00 2.10 2.20 4.00 4.10

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Keywords          : kbCompiler kbCRT kbVC kbprb 
Technology        : kbVCsearch kbVC400 kbAudDeveloper kbVC410 kbVC32bitSearch
Version           : :4.0,4.1
Issue type        : kbprb

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