C6293

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warning C6293: Ill-defined for-loop: counts down from minimum

This warning indicates that a for-loop might not function as intended. It occurs when a loop counts down from a minimum, but has a higher termination condition.

A signed —or unsigned—index variable together with a negative increment will cause the loop to count negative until an overflow occurs. This will terminate the loop.

The following sample code generates this warning:

void f( )  
{  
   signed char i;  
  
   for (i = 0; i < 100; i--)  
   {  
      // code ...  
   }  
}  
  

To correct this warning, use the following code:

void f( )  
{  
   signed char i;  
  
   for (i = 0; i < 100; i++)  
   {  
      // code ...  
   }  
}