Doxygen always adds certain spaces when expanding PREDEFINED macros. This can lead to errors. Following example (I will attach the files):

/** Declares an empty constructor and destructor for the given class. */
#define DECLARE_EMPTY_CTOR_DTOR(cls) cls(); virtual ~cls();

/** This is a sample class. */
class fooclass
{
    DECLARE_EMPTY_CTOR_DTOR(fooclass)
};

fooclass::fooclass()
{
}

fooclass::~fooclass()
{
}


After 'doxygen -d Preprocess' I get

...
00008 /** This is a sample class. */
00009 class fooclass
00010 {
00011      fooclass  (); virtual ~  fooclass  ();
00012 };
...


The expected output would be


class fooclass
{
    fooclass(); virtual ~fooclass();
}


The wrongly expanded macro leads to the following warning:

foo.cpp:18: warning: documented symbol `fooclass::~fooclass' was not declared or defined.