Question

I have the following macro:

#define IF_TRACE_ENABLED(level)  if (IsTraceEnabled(level))

The user code should look following:

IF_TRACE_ENABLED(LEVEL1)
{
    ... some very smart code
}

The emphasis here on curly brackets – I want to prevent “if” from macro to “eat” other code:

if (...)
   IF_TRACE_ENABLED(LEVEL1)
      printf(....);
else
   bla bla bla

In this example IF_TRACE_ENABLED “eats” else block.

Is there way to enforce user code not compile without curly brakes or there are other to define the macro to achieve the safety?

Answer 1

This doesn’t force the user of the macro to use braces, but it will prevent an else clause from being unintentionally eaten:

#define IF_TRACE_ENABLED(level)  if (!IsTraceEnabled(level)) {} else 

A side note: braces around the printf() in the second example of the question wouldn’t have fixed the problem – the else associated with bla bla bla would still be bound to the if statement in the macro.