INFO: Character Parameters May Be Prototyped as Integers (51474)
The information in this article applies to:
- The C Run-Time (CRT), when used with:
- Microsoft Visual C++ for Windows, 16-bit edition 1.0
- Microsoft Visual C++ for Windows, 16-bit edition 1.5
- Microsoft Visual C++, 32-bit Editions 1.0
- Microsoft Visual C++, 32-bit Editions 2.0
- Microsoft Visual C++, 32-bit Editions 4.0
- Microsoft Visual C++, 32-bit Editions 5.0
- Microsoft Visual C++, 32-bit Editions 6.0
This article was previously published under Q51474 SUMMARY
In Microsoft C, there are some functions in the run-time library that
take character values as parameters (for example, memccpy, memset, and
so on) and that are prototyped as taking integers. This is not a
documentation error and your program will work correctly if a character
value is passed in the place of the integer parameter (automatic type
conversion takes care of this).
The integer value is specified because when the compiler pushes
parameters on the stack so that the function being called can use
them, it always pushes them in integer sized increments. In a 16-bit
program where an integer is 2 bytes, 2 bytes will be pushed on the
stack regardless of whether the value is an integer or a character. In
a 32-bit program where an integer is always 4 bytes, 4 bytes will be
pushed on the stack regardless of whether the value is an integer,
long, short, or character.
Therefore, to simplify, the function is prototyped as receiving an
integer.
| Modification Type: | Major | Last Reviewed: | 12/11/2003 |
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| Keywords: | kbCRT kbinfo KB51474 kbAudDeveloper |
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