error: ISO C++ forbids declaration of ‘type name’ with no type [-fpermissive]

masa4

I am developing a qt project, with some generic classes that use glib. Because of this i was getting error about signals but i solved it with adding #undef signals #define signals keywords before and after glib includes. Now i started to add this generic headers to my headers. My include hierarchy like this:
HEADER1(generic header file):

#undef signals
#include <glib.h>
...
#define signals

HEADER2(generic class' header):

#include "header1.h"

HEADER3(my class header):

#include "header2.h"

But now i am again in trouble with signals keyword. When i built it i got

../../myproj/header3.h:39:5: error: ISO C++ forbids declaration of ‘type name’ with no type [-fpermissive]
../../myproj/header3.h:38:8: error: expected ‘;’ at end of member declaration
   38 | signals:

When i include header2 to my .cpp, i dont get this error. when including it to my header files, i got error and It gives me "signals" redefined warning too. How can i work around the issue? What is wrong now?

J.Hilk

@masa4 see this section of the documentation:
https://doc.qt.io/qt-6/signalsandslots.html#using-qt-with-3rd-party-signals-and-slots

in essence, "Disable" qt signals and slots keywords and replace them with Q_SIGNALS and QSLOTS

masa4

@J-Hilk Thanks, I didnt want to replace them but in the end i did it. This one is most painless solution.