Compiler Warning (level 4) C4289

The latest version of this topic can be found at Compiler Warning (level 4) C4289.

nonstandard extension used : 'var' : loop control variable declared in the for-loop is used outside the for-loop scope

When compiling with /Ze and /Zc:forScope-, a variable declared in a for loop was used after the for-loop scope.

See /Zc:forScope for information about how to specify standard behavior in for loops with /Ze.

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

The following sample generates C4289:

// C4289.cpp  
// compile with: /W4 /Zc:forScope-  
#pragma warning(default:4289)  
int main() {  
   for (int i = 0 ; ; )   // C4289  
      break;  
   i++;  
}