Question

I have a macro that looks like this:

#define coutError    if (VERBOSITY_SETTING >= VERBOSITY_ERROR)    ods() 

where ods() is a class that behaves similarly to cout, and VERBOSITY_SETTING is a global variable. There are a few of these for different verbosity settings, and it allows the code to look something like this:

if (someErrorCondition) {     // ... do things relating to the error condition ...      coutError << 'Error condition occurred'; } 

And there is functionality in this framework to set the verbosity, etc. However, the obvious pattern breaks when not using braces in something like this:

void LightSwitch::TurnOn() {     if (!PowerToSwitch)         coutError << 'No power!';     else         SwitchOn = true; } 

because of the macro, will turn into this:

void LightSwitch::TurnOn() {     if (!PowerToSwitch)         if (VERBOSITY_SETTING >= VERBOSITY_ERROR)             ods() << 'No power!';         else             SwitchOn = true; } 

Which is not the intended functionality of the if statement.

Now, I understand a way to fix this macro properly so it doesn’t cause this problem, but I’d like to run an audit on the code and find any place that has this pattern of ‘if (…) coutError << …; else’ to find out if there are any other cases where this happens to make sure that when fixing the macro, it will indeed be correct functionality.

I can use any language/tool to find this, I just want to know the best way of doing that.

Answer 1

You could try – temporarily – modifying the macro to something like this, and see what doesn’t compile…

#define coutError {} if (VERBOSITY_SETTING >= VERBOSITY_ERROR) ods() 

The ‘else’ clauses should now give errors.