Uncrustify currently does not keep track of braces that span multiple preprocessor blocks and therefore will abort and complain about missing braces in code like the example below:

#if(1)
  if(true)
  {
#endif
    int i = 1;
#if(1)
  }
#endif

If you want to use Uncrustify on your code, avoid this kind of brace placement until this problem is fixed.

C++ is a notoriously hard to parse language as its grammar is ambiguous, context-dependent and potentially requires infinite lookahead to resolve some ambiguities.

Currently Uncrustify's parser is not well equipped to handle such edge cases well. This construct, for example, is problematic:

    A b(c*d);

The above example could either be:

• A declaration of a function b with A as return type, c* as a parameter type, and d as the parameter name

  or

• A declaration of a variable b of type A, with a constructor call with the parameter of variable c multiplied by variable d

To remove the ambiguity in the above example, parenthesis can be added around c so that the construct will be parsed as a variable declaration.

    A b((c)*d);