Microsoft KB Archive/42562

= PRB: C4057 or C4133 Occur Unexpectedly =

Article ID: 42562

Article Last Modified on 7/5/2005

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APPLIES TO


 * Microsoft Visual C++ 1.0 Professional Edition
 * Microsoft Visual C++ 1.5 Professional Edition
 * Microsoft Visual C++ 1.0 Professional Edition
 * Microsoft Visual C++ 2.0 Professional Edition
 * Microsoft Visual C++ 4.0 Standard Edition
 * Microsoft Visual C++ 5.0 Standard Edition
 * Microsoft Visual C++ 6.0 Service Pack 5

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This article was previously published under Q42562





SYMPTOMS
Using the Microsoft C/C++ compiler (CL.EXE) versions 7.0, 8.0, and 8.0c for MS-DOS, the following warning is generated:

  C4057: 'argument': indirection to slightly different base types

Using the Microsoft C/C++ compiler (CL.EXE) versions 8.0 and 9.0 (32-bit edition), the following warning is generated:

  C4133: 'argument' : incompatible types-from 'short *' to 'int *'

Using the Microsoft C/C++ compiler (CL.EXE) version 10.0 and higher (32-bit edition), the following warning is generated:

  C4133: 'function' : incompatible types-from 'short *' to 'int *'



CAUSE
These warnings are expected behavior. According to ANSI standards, variables of type int* are different from variables of type short*. And, although the compiler may be able to perform an implicit promotion/demotion among intergral types (char, short, int, long, etc.), pointers are not of integral type.



RESOLUTION
To remove these warnings, use an appropriate cast to instruct the compiler to explicitly convert the value from its current data type to the desired.



MORE INFORMATION
The only restriction on the size of the short given by the ANSI standard is that it NOT be longer than an integer. Code should be written with this in mind so that it will be portable. In many implementations, such as WINDOWS NT, integers are not the same as shorts.

Compiling the following program will generate the discussed warning:

Sample Code
/* Compile options needed: /c /W4

void ShortFunc( short, short * ); void Func( int, int * );

void main {   short sTest; short *sPoint;

ShortFunc( sTest, sPoint ); Func( sTest, sPoint ); /*  Generates warning  */ Func( sTest, (int *)sPoint ); /*  Does not generate warning  */ }

Additional query words: 8.00 8.00c 9.00

Keywords: kbprb KB42562

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