# linker issues when building mediasoup-broadcaster-demo

**URL:** https://mediasoup.discourse.group/t/linker-issues-when-building-mediasoup-broadcaster-demo/500
**Category:** mediasoup libraries
**Created:** [December 27, 2019, 12:30pm UTC](https://mediasoup.discourse.group/t/linker-issues-when-building-mediasoup-broadcaster-demo/500 "2019-12-27T12:30:15Z")
**Posts on this page:** 9
**Page:** 1

<div class="post-metadata">

### Author: ![robertkrahn](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/robertkrahn/32/199_2.png) [@robertkrahn](https://mediasoup.discourse.group/u/robertkrahn)
#### Post date: [December 27, 2019, 12:30pm UTC](https://mediasoup.discourse.group/t/linker-issues-when-building-mediasoup-broadcaster-demo/500/1 "2019-12-27T12:30:15Z")

</div>

I’m trying to build mediasoup-broadcaster-demo and run into linker errors. I’ve a working libwebrtc m74 build.

```auto
[80%] Linking CXX executable broadcaster
CMakeFiles/broadcaster.dir/src/Broadcaster.cpp.o: In function `std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > cricket::ToStringIfSet<bool>(char const*, absl::optional<bool> const&)':
Broadcaster.cpp:(.text+0x321f): undefined reference to `rtc::ToString[abi:cxx11](bool)'
CMakeFiles/broadcaster.dir/src/Broadcaster.cpp.o: In function `std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > cricket::ToStringIfSet<int>(char const*, absl::optional<int> const&)':
Broadcaster.cpp:(.text+0x338f): undefined reference to `rtc::ToString[abi:cxx11](int)'
CMakeFiles/broadcaster.dir/src/Broadcaster.cpp.o: In function `mediasoupclient::PeerConnection::RTCStatsCollectorCallback::OnStatsDelivered(rtc::scoped_refptr<webrtc::RTCStatsReport const> const&)':
Broadcaster.cpp:(.text._ZN15mediasoupclient14PeerConnection25RTCStatsCollectorCallback16OnStatsDeliveredERKN3rtc13scoped_refptrIKN6webrtc14RTCStatsReportEEE[_ZN15mediasoupclient14PeerConnection25RTCStatsCollectorCallback16OnStatsDeliveredERKN3rtc13scoped_refptrIKN6webrtc14RTCStatsReportEEE]+0x4a): undefined reference to `webrtc::RTCStatsReport::ToJson[abi:cxx11]() const'
CMakeFiles/broadcaster.dir/src/Broadcaster.cpp.o:(.data.rel.ro._ZTVN15mediasoupclient14PeerConnection32CreateSessionDescriptionObserverE[_ZTVN15mediasoupclient14PeerConnection32CreateSessionDescriptionObserverE]+0x40): undefined reference to `webrtc::CreateSessionDescriptionObserver::OnFailure(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'
CMakeFiles/broadcaster.dir/src/Broadcaster.cpp.o:(.data.rel.ro._ZTVN15mediasoupclient14PeerConnection29SetSessionDescriptionObserverE[_ZTVN15mediasoupclient14PeerConnection29SetSessionDescriptionObserverE]+0x40): undefined reference to `webrtc::SetSessionDescriptionObserver::OnFailure(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'
CMakeFiles/broadcaster.dir/src/Broadcaster.cpp.o:(.data.rel.ro._ZTIN15mediasoupclient14PeerConnection32CreateSessionDescriptionObserverE[_ZTIN15mediasoupclient14PeerConnection32CreateSessionDescriptionObserverE]+0x10): undefined reference to `typeinfo for webrtc::CreateSessionDescriptionObserver'
CMakeFiles/broadcaster.dir/src/Broadcaster.cpp.o:(.data.rel.ro._ZTIN15mediasoupclient14PeerConnection29SetSessionDescriptionObserverE[_ZTIN15mediasoupclient14PeerConnection29SetSessionDescriptionObserverE]+0x10): undefined reference to `typeinfo for webrtc::SetSessionDescriptionObserver'
CMakeFiles/broadcaster.dir/src/main.cpp.o: In function `std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > cricket::ToStringIfSet<bool>(char const*, absl::optional<bool> const&)':
...

```

This looks to me like a gcc/clang stdlib issue. I get this error both with a libwebrtc build with clang and gcc. Switching to clang for the mediasoup-broadcaster-demo build gives me slightly different errors

```auto
[80%] Linking CXX executable broadcaster
CMakeFiles/broadcaster.dir/src/Broadcaster.cpp.o: In function `mediasoupclient::PeerConnection::RTCStatsCollectorCallback::OnStatsDelivered(rtc::scoped_refptr<webrtc::RTCStatsReport const> const&)':
Broadcaster.cpp:(.text._ZN15mediasoupclient14PeerConnection25RTCStatsCollectorCallback16OnStatsDeliveredERKN3rtc13scoped_refptrIKN6webrtc14RTCStatsReportEEE[_ZN15mediasoupclient14PeerConnection25RTCStatsCollectorCallback16OnStatsDeliveredERKN3rtc13scoped_refptrIKN6webrtc14RTCStatsReportEEE]+0x2f): undefined reference to `webrtc::RTCStatsReport::ToJson[abi:cxx11]() const'
CMakeFiles/broadcaster.dir/src/Broadcaster.cpp.o:(.rodata._ZTVN15mediasoupclient14PeerConnection29SetSessionDescriptionObserverE[_ZTVN15mediasoupclient14PeerConnection29SetSessionDescriptionObserverE]+0x40): undefined reference to `webrtc::SetSessionDescriptionObserver::OnFailure(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'
CMakeFiles/broadcaster.dir/src/Broadcaster.cpp.o:(.rodata._ZTIN15mediasoupclient14PeerConnection29SetSessionDescriptionObserverE[_ZTIN15mediasoupclient14PeerConnection29SetSessionDescriptionObserverE]+0x10): undefined reference to `typeinfo for webrtc::SetSessionDescriptionObserver'
CMakeFiles/broadcaster.dir/src/Broadcaster.cpp.o:(.rodata._ZTVN15mediasoupclient14PeerConnection32CreateSessionDescriptionObserverE[_ZTVN15mediasoupclient14PeerConnection32CreateSessionDescriptionObserverE]+0x40): undefined reference to `webrtc::CreateSessionDescriptionObserver::OnFailure(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'
CMakeFiles/broadcaster.dir/src/Broadcaster.cpp.o:(.rodata._ZTIN15mediasoupclient14PeerConnection32CreateSessionDescriptionObserverE[_ZTIN15mediasoupclient14PeerConnection32CreateSessionDescriptionObserverE]+0x10): undefined reference to `typeinfo for webrtc::CreateSessionDescriptionObserver'
CMakeFiles/broadcaster.dir/src/peerConnectionUtils.cpp.o: In function `createPeerConnectionFactory()':
peerConnectionUtils.cpp:(.text+0x430): undefined reference to `rtc::Thread::SetName(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, void const*)'
...

```

Any hints of how to complete this build successfully?

Thanks!  
Robert

---

<div class="post-metadata">

### Author: ![robertkrahn](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/robertkrahn/32/199_2.png) [@robertkrahn](https://mediasoup.discourse.group/u/robertkrahn)
#### Post date: [December 27, 2019, 1:13pm UTC](https://mediasoup.discourse.group/t/linker-issues-when-building-mediasoup-broadcaster-demo/500/2 "2019-12-27T13:13:56Z")

</div>

I missed

> Build libwebrtc with the ‘use\_custom\_libcxx=false’ `gn gen` argument to force it use of the system libstdc++.

at [mediasoup :: Installation](https://mediasoup.org/documentation/v3/libmediasoupclient/installation/)

So this helped a bit but still linker errors…

```auto
[80%] Linking CXX executable broadcaster
CMakeFiles/broadcaster.dir/src/Broadcaster.cpp.o:(.data.rel.ro._ZTIN15mediasoupclient14PeerConnection32CreateSessionDescriptionObserverE[_ZTIN15mediasoupclient14PeerConnection32CreateSessionDescriptionObserverE]+0x10): undefined reference to `typeinfo for webrtc::CreateSessionDescriptionObserver'
CMakeFiles/broadcaster.dir/src/Broadcaster.cpp.o:(.data.rel.ro._ZTIN15mediasoupclient14PeerConnection29SetSessionDescriptionObserverE[_ZTIN15mediasoupclient14PeerConnection29SetSessionDescriptionObserverE]+0x10): undefined reference to `typeinfo for webrtc::SetSessionDescriptionObserver'
CMakeFiles/broadcaster.dir/src/peerConnectionUtils.cpp.o:(.data.rel.ro._ZTI19CapturerTrackSource[_ZTI19CapturerTrackSource]+0x10): undefined reference to `typeinfo for webrtc::VideoTrackSource'
CMakeFiles/broadcaster.dir/src/peerConnectionUtils.cpp.o:(.data.rel.ro._ZTIN6webrtc25VideoTrackSourceInterfaceE[_ZTIN6webrtc25VideoTrackSourceInterfaceE]+0x18): undefined reference to `typeinfo for webrtc::MediaSourceInterface'
/path/to/webrtc-google-3/src/out/gcc/obj/libwebrtc.a(audio_device_alsa_linux.o): In function `webrtc::AudioDeviceLinuxALSA::Init()':
/path/to/webrtc-google-3/src/out/gcc/../../modules/audio_device/linux/audio_device_alsa_linux.cc:158: undefined reference to `XOpenDisplay'
/path/to/webrtc-google-3/src/out/gcc/obj/libwebrtc.a(audio_device_alsa_linux.o): In function `webrtc::AudioDeviceLinuxALSA::Terminate()':
/path/to/webrtc-google-3/src/out/gcc/../../modules/audio_device/linux/audio_device_alsa_linux.cc:202: undefined reference to `XCloseDisplay'
/path/to/webrtc-google-3/src/out/gcc/obj/libwebrtc.a(audio_device_alsa_linux.o): In function `webrtc::AudioDeviceLinuxALSA::KeyPressed() const':
/path/to/webrtc-google-3/src/out/gcc/../../modules/audio_device/linux/audio_device_alsa_linux.cc:1640: undefined reference to `XQueryKeymap'
/path/to/webrtc-google-3/src/out/gcc/obj/libwebrtc.a(audio_device_pulse_linux.o): In function `webrtc::AudioDeviceLinuxPulse::Init()':
/path/to/webrtc-google-3/src/out/gcc/../../modules/audio_device/linux/audio_device_pulse_linux.cc:154: undefined reference to `XOpenDisplay'
/path/to/webrtc-google-3/src/out/gcc/obj/libwebrtc.a(audio_device_pulse_linux.o): In function `webrtc::AudioDeviceLinuxPulse::Terminate()':
/path/to/webrtc-google-3/src/out/gcc/../../modules/audio_device/linux/audio_device_pulse_linux.cc:213: undefined reference to `XCloseDisplay'
/path/to/webrtc-google-3/src/out/gcc/obj/libwebrtc.a(audio_device_pulse_linux.o): In function `webrtc::AudioDeviceLinuxPulse::KeyPressed() const':
/path/to/webrtc-google-3/src/out/gcc/../../modules/audio_device/linux/audio_device_pulse_linux.cc:2278: undefined reference to `XQueryKeymap'
collect2: error: ld returned 1 exit status

```

Any ideas what that could be?

---

<div class="post-metadata">

### Author: ![robertkrahn](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/robertkrahn/32/199_2.png) [@robertkrahn](https://mediasoup.discourse.group/u/robertkrahn)
#### Post date: [December 27, 2019, 1:27pm UTC](https://mediasoup.discourse.group/t/linker-issues-when-building-mediasoup-broadcaster-demo/500/3 "2019-12-27T13:27:27Z")

</div>

Alright, using gcc with `$ gn gen out/mybuild-m74 --args='is_debug=false is_component_build=false is_clang=false rtc_include_tests=false rtc_use_h264=true rtc_enable_protobuf=false use_rtti=true use_custom_libcxx=false treat_warnings_as_errors=false use_ozone=true'` (as mentioned in the documentation) worked. Just needed some rubber ducking.

---

<div class="post-metadata">

### Author: ![ibc](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/ibc/32/1540_2.png) [@ibc](https://mediasoup.discourse.group/u/ibc)
#### Post date: [December 27, 2019, 2:01pm UTC](https://mediasoup.discourse.group/t/linker-issues-when-building-mediasoup-broadcaster-demo/500/4 "2019-12-27T14:01:27Z")

</div>

Just take into account that you did not even tell which OS you are running.

BTW: is that working command the same as the one exposed in the documentation?

---

<div class="post-metadata">

### Author: ![robertkrahn](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/robertkrahn/32/199_2.png) [@robertkrahn](https://mediasoup.discourse.group/u/robertkrahn)
#### Post date: [December 27, 2019, 3:11pm UTC](https://mediasoup.discourse.group/t/linker-issues-when-building-mediasoup-broadcaster-demo/500/5 "2019-12-27T15:11:50Z")

</div>

I’m using Ubuntu 18.04. And yes, the build command for libwebrtc is from the documentation.

---

<div class="post-metadata">

### Author: ![ibc](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/ibc/32/1540_2.png) [@ibc](https://mediasoup.discourse.group/u/ibc)
#### Post date: [December 27, 2019, 3:14pm UTC](https://mediasoup.discourse.group/t/linker-issues-when-building-mediasoup-broadcaster-demo/500/6 "2019-12-27T15:14:44Z")

</div>

So the doc is fine, right? 🙂

Note however that building libwebrtc is out of the scope of libmediasoupclient, we just provide some hints but those may need to change depending on libwebrtc version or OS.

---

<div class="post-metadata">

### Author: ![robertkrahn](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/robertkrahn/32/199_2.png) [@robertkrahn](https://mediasoup.discourse.group/u/robertkrahn)
#### Post date: [December 27, 2019, 3:29pm UTC](https://mediasoup.discourse.group/t/linker-issues-when-building-mediasoup-broadcaster-demo/500/7 "2019-12-27T15:29:49Z")

</div>

Yes, the docs are good and I didn’t intend to suggest otherwise. I’ve added the build command above as it is the direct answer to my question. I missed the build section when I first started out, my apologies for that. Thanks for putting it out there!

---

<div class="post-metadata">

### Author: ![ibc](https://yyz2.discourse-cdn.com/free1/user_avatar/mediasoup.discourse.group/ibc/32/1540_2.png) [@ibc](https://mediasoup.discourse.group/u/ibc)
#### Post date: [December 27, 2019, 3:36pm UTC](https://mediasoup.discourse.group/t/linker-issues-when-building-mediasoup-broadcaster-demo/500/8 "2019-12-27T15:36:18Z")

</div>

Thanks. If anyway you see something that can be improved in the documentation, don’t hesitate to tell it.

---

<div class="post-metadata">

### Author: ![dev.ivan.h](https://avatars.discourse-cdn.com/v4/letter/d/e9bcb4/32.png) [@dev.ivan.h](https://mediasoup.discourse.group/u/dev.ivan.h)
#### Post date: [June 14, 2022, 9:02am UTC](https://mediasoup.discourse.group/t/linker-issues-when-building-mediasoup-broadcaster-demo/500/9 "2022-06-14T09:02:08Z")

</div>

Looks like I have the same issues on Ubuntu 20.04.  
I have built WebRTC of version `branch-heads/4606` with all the arguments described above and have all these linker errors.  
Should any specific linker options be added or something?