Microsoft KB Archive/41374

= Assignment of Void Pointer Does Not Give Warning Message =

Article ID: 41374

Article Last Modified on 7/5/2005

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APPLIES TO


 * Microsoft C Professional Development System 6.0
 * Microsoft C Professional Development System 6.0a
 * Microsoft C Professional Development System 6.0a
 * Microsoft C Professional Development System 6.0
 * Microsoft C Professional Development System 6.0a
 * Microsoft C/C++ Professional Development System 7.0
 * Microsoft Visual C++ 1.0 Professional Edition
 * Microsoft Visual C++ 1.5 Professional Edition
 * Microsoft Visual C++ 1.51
 * Microsoft Visual C++ 2.0 Professional Edition
 * Microsoft Visual C++ 2.1

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This article was previously published under Q41374



SUMMARY
The Sample Code below shows an inconsistency with the way that the Microsoft compilers listed above deal with pointer checking. The ANSI standard is unclear about whether an assignment to a void pointer should be checked to see if it is being assigned a nonpointer variable. The code below shows that character pointers are checked while void pointers are not; the code will generate the following warnings:

16-bit compilers
The compiler generates the following warning for the void pointer in the sample code as well as the character pointer: C4047: '=' different levels of indirection

32-bit compilers
The compiler generates the following warming with the sample code: C4047: &quot;=&quot;: 'void *' differs in levels of indirection from 'int'

7.0 and later
Compiler versions 7.0 and later generate the following error in both cases if the program is compiled as a C++ program (.cpp extension).

error C2446: '=' : no conversion from 'int ' to 'void *'



Sample Code:
/* Compile options needed: none

int i;        /* i could be float, double, char, long, or unsigned */ char *p; void *v;

void main {  p = i;      /* This will give a warning message */ v = i; }

Additional query words: kbinf 6.00 6.00a 6.00ax 7.00 8.00 8.00c 9.00 9.10 1.00 1.50 2.00 2.10

Keywords: KB41374

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