PRB: Sizeof Constant Character Returns Different Values
Article ID: 150380
Article Last Modified on 10/24/2003
APPLIES TO
- Microsoft Visual C++ 4.0 Professional Edition
- Microsoft Visual C++ 4.1 Subscription
- Microsoft Visual C++ 5.0 Learning Edition
This article was previously published under Q150380
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
Keywords: kbcrt kbprb kbcompiler KB150380