Compiler Warning (level 1) C4548

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The latest version of this topic can be found at Compiler Warning (level 1) C4548.

expression before comma has no effect; expected expression with side-effect

The compiler detected an ill-formed comma expression.

This warning is off by default. For more information, see Compiler Warnings That Are Off by Default.

The following sample generates C4548:

// C4548.cpp  
// compile with: /W1  
#pragma warning (default : 4548)  
int main()  
{  
   int i = 0, k = 0;  
  
   if ( i, k )   // C4548  
   // try the following line instead  
   // if ( i = 0, k )  
      i++;  
}