PRB: Sizeof Constant Character Returns Different Values

 Last reviewed: May 7, 1996
Article ID: Q150380
The information in this article applies to:
  • The Microsoft C/C++ Compiler (CL.EXE) included with: Visual C++, 32-bit Edition, versions 4.0, 4.1

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 reference words: 2.00 2.10 2.20 4.00 4.10
KBCategory: kbprg kbtshoot kbprb
KBSubcategory: CLIss CRTIss



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Last reviewed: May 7, 1996
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