Compiler Warning (level 1) C4555

expression has no effect; expected expression with side-effect

This warning informs you when an expression has no effect.

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

For example:

// C4555.cpp
// compile with: /W1
#pragma warning(default:4555)

void func1()
{
   1;   // C4555
}

void func2()
{
   int x;
   x;   // C4555
}

int main()
{
}