Error building Qt + libwebrtc

[mvquezm]

Greetings, I'm trying to build a basic console project using Qt6 (Core, Multimedia and Network modules) plus google libwebrtc library.

Compile output error:

In file included from /Users/..../test//services/webrtctest.cpp:1:
In file included from /Users/..../test//services/webrtctest.h:5:
In file included from /Users/..../test//build/Qt_6_7_2_for_macOS-Debug/_deps/3rd-party-lib/include/mediasoupclient.hpp:4:
In file included from /Users/..../test//build/Qt_6_7_2_for_macOS-Debug/_deps/3rd-party-lib/include/Device.hpp:4:
In file included from /Users/..../test//build/Qt_6_7_2_for_macOS-Debug/_deps/3rd-party-lib/include/Handler.hpp:4:
In file included from /Users/..../test//build/Qt_6_7_2_for_macOS-Debug/_deps/3rd-party-lib/include/PeerConnection.hpp:5:
In file included from /Users/.../webrtc-checkout/src/api/peer_connection_interface.h:83:
In file included from /Users/.../webrtc-checkout/src/api/async_resolver_factory.h:14:
In file included from /Users/.../webrtc-checkout/src/rtc_base/async_resolver_interface.h:17:
/Users/.../webrtc-checkout/src/rtc_base/third_party/sigslot/sigslot.h:327:17: error: expected ')'
void emit(Args... args) const {
^
/Users/.../webrtc-checkout/src/rtc_base/third_party/sigslot/sigslot.h:327:12: note: to match this '('
void emit(Args... args) const {
^

Any advise? Thanks!

[Pl45m4]

@mvquezm said in Error building Qt + libwebrtc:

/Users/.../webrtc-checkout/src/rtc_base/third_party/sigslot/sigslot.h:327:17: error: expected ')'
void emit(Args... args) const {
^
/Users/.../webrtc-checkout/src/rtc_base/third_party/sigslot/sigslot.h:327:12: note: to match this '('
void emit(Args... args) const {

I have zero knowledge about libwebrtc, but it looks like this thirdparty lib is using functions/methods and other symbols named emit ... in its own signaling system called "sigslot".
emit is a preprocessor macro which actually expands to "nothing", used by Qt's Signal / Slot mechanism.

In case there are conficts with thirdparty stuff, you could try to configure your project using the QT_NO_KEYWORDS option

Add one of those to your CMake:

target_compile_definitions(Your_Target PRIVATE QT_NO_KEYWORDS)
or
ADD_DEFINITIONS(-DQT_NO_KEYWORDS)

When emitting a Qt signal, you can use Q_EMIT instead or omit it completely.
Same for signals or slots in your headers... use their Q_ siblings :)

Read here for further info

• https://doc.qt.io/qt-6/signalsandslots.html#using-qt-with-3rd-party-signals-and-slots

[mvquezm]

Thank you so much @Pl45m4