Compiler Warning (level 3) C4287
Collapse the table of content
Expand the table of content
Important This document may not represent best practices for current development, links to downloads and other resources may no longer be valid. Current recommended version can be found here. ArchiveDisclaimer

Compiler Warning (level 3) C4287

Error Message

'operator' : unsigned/negative constant mismatch

An unsigned variable was used in an operation with a negative number.

This warning is off by default. See Compiler Warnings That Are Off by Default for more information.


The following sample generates C4287:

// C4287.cpp
// compile with: /W3
#pragma warning(default : 4287)
#include <stdio.h>

int main()
    unsigned int u = 1;
    if (u < -1)   // C4287
        printf_s("u LT -1");
        printf_s("u !LT -1");
    return 0;
© 2016 Microsoft