warnings: implicit capture of ‘this’ via ‘[=]’ is deprecated in C++20 [-Wdeprecated]

[gocarlos]

In file included from /home/gocarlos/.conan/data/paho-mqtt-cpp/1.0.1/_/_/package/de1bbfb8eed70320d3c37ce9521ac7e673c69477/include/mqtt/async_client.h:37,
/home/gocarlos/.conan/data/paho-mqtt-cpp/1.0.1/_/_/package/de1bbfb8eed70320d3c37ce9521ac7e673c69477/include/mqtt/thread_queue.h: In lambda function:
/home/gocarlos/.conan/data/paho-mqtt-cpp/1.0.1/_/_/package/de1bbfb8eed70320d3c37ce9521ac7e673c69477/include/mqtt/thread_queue.h:153:25: warning: implicit capture of ‘this’ via ‘[=]’ is deprecated in C++20 [-Wdeprecated]
  153 |    notFullCond_.wait(g, [=]{return que_.size() < cap_;});
      |                         ^
/home/gocarlos/.conan/data/paho-mqtt-cpp/1.0.1/_/_/package/de1bbfb8eed70320d3c37ce9521ac7e673c69477/include/mqtt/thread_queue.h:153:25: note: add explicit ‘this’ or ‘*this’ capture
/home/gocarlos/.conan/data/paho-mqtt-cpp/1.0.1/_/_/package/de1bbfb8eed70320d3c37ce9521ac7e673c69477/include/mqtt/thread_queue.h: In lambda function:
/home/gocarlos/.conan/data/paho-mqtt-cpp/1.0.1/_/_/package/de1bbfb8eed70320d3c37ce9521ac7e673c69477/include/mqtt/thread_queue.h:190:55: warning: implicit capture of ‘this’ via ‘[=]’ is deprecated in C++20 [-Wdeprecated]
  190 |   if (n >= cap_ && !notFullCond_.wait_for(g, relTime, [=]{return que_.size() < cap_;}))
      |                                                       ^
/home/gocarlos/.conan/data/paho-mqtt-cpp/1.0.1/_/_/package/de1bbfb8eed70320d3c37ce9521ac7e673c69477/include/mqtt/thread_queue.h:190:55: note: add explicit ‘this’ or ‘*this’ capture
/home/gocarlos/.conan/data/paho-mqtt-cpp/1.0.1/_/_/package/de1bbfb8eed70320d3c37ce9521ac7e673c69477/include/mqtt/thread_queue.h: In lambda function:
/home/gocarlos/.conan/data/paho-mqtt-cpp/1.0.1/_/_/package/de1bbfb8eed70320d3c37ce9521ac7e673c69477/include/mqtt/thread_queue.h:213:57: warning: implicit capture of ‘this’ via ‘[=]’ is deprecated in C++20 [-Wdeprecated]
  213 |   if (n >= cap_ && !notFullCond_.wait_until(g, absTime, [=]{return que_.size() < cap_;}))
      |                                                         ^
/home/gocarlos/.conan/data/paho-mqtt-cpp/1.0.1/_/_/package/de1bbfb8eed70320d3c37ce9521ac7e673c69477/include/mqtt/thread_queue.h:213:57: note: add explicit ‘this’ or ‘*this’ capture
/home/gocarlos/.conan/data/paho-mqtt-cpp/1.0.1/_/_/package/de1bbfb8eed70320d3c37ce9521ac7e673c69477/include/mqtt/thread_queue.h: In lambda function:
/home/gocarlos/.conan/data/paho-mqtt-cpp/1.0.1/_/_/package/de1bbfb8eed70320d3c37ce9521ac7e673c69477/include/mqtt/thread_queue.h:232:26: warning: implicit capture of ‘this’ via ‘[=]’ is deprecated in C++20 [-Wdeprecated]
  232 |    notEmptyCond_.wait(g, [=]{return !que_.empty();});
      |                          ^
/home/gocarlos/.conan/data/paho-mqtt-cpp/1.0.1/_/_/package/de1bbfb8eed70320d3c37ce9521ac7e673c69477/include/mqtt/thread_queue.h:232:26: note: add explicit ‘this’ or ‘*this’ capture
/home/gocarlos/.conan/data/paho-mqtt-cpp/1.0.1/_/_/package/de1bbfb8eed70320d3c37ce9521ac7e673c69477/include/mqtt/thread_queue.h: In lambda function:
/home/gocarlos/.conan/data/paho-mqtt-cpp/1.0.1/_/_/package/de1bbfb8eed70320d3c37ce9521ac7e673c69477/include/mqtt/thread_queue.h:250:26: warning: implicit capture of ‘this’ via ‘[=]’ is deprecated in C++20 [-Wdeprecated]
  250 |    notEmptyCond_.wait(g, [=]{return !que_.empty();});
      |                          ^
/home/gocarlos/.conan/data/paho-mqtt-cpp/1.0.1/_/_/package/de1bbfb8eed70320d3c37ce9521ac7e673c69477/include/mqtt/thread_queue.h:250:26: note: add explicit ‘this’ or ‘*this’ capture
/home/gocarlos/.conan/data/paho-mqtt-cpp/1.0.1/_/_/package/de1bbfb8eed70320d3c37ce9521ac7e673c69477/include/mqtt/thread_queue.h: In lambda function:
/home/gocarlos/.conan/data/paho-mqtt-cpp/1.0.1/_/_/package/de1bbfb8eed70320d3c37ce9521ac7e673c69477/include/mqtt/thread_queue.h:294:53: warning: implicit capture of ‘this’ via ‘[=]’ is deprecated in C++20 [-Wdeprecated]
  294 |   if (n == 0 && !notEmptyCond_.wait_for(g, relTime, [=]{return !que_.empty();}))
      |                                                     ^
/home/gocarlos/.conan/data/paho-mqtt-cpp/1.0.1/_/_/package/de1bbfb8eed70320d3c37ce9521ac7e673c69477/include/mqtt/thread_queue.h:294:53: note: add explicit ‘this’ or ‘*this’ capture
/home/gocarlos/.conan/data/paho-mqtt-cpp/1.0.1/_/_/package/de1bbfb8eed70320d3c37ce9521ac7e673c69477/include/mqtt/thread_queue.h: In lambda function:
/home/gocarlos/.conan/data/paho-mqtt-cpp/1.0.1/_/_/package/de1bbfb8eed70320d3c37ce9521ac7e673c69477/include/mqtt/thread_queue.h:318:55: warning: implicit capture of ‘this’ via ‘[=]’ is deprecated in C++20 [-Wdeprecated]
  318 |   if (n == 0 && !notEmptyCond_.wait_until(g, absTime, [=]{return !que_.empty();}))
      |                                                       ^
/home/gocarlos/.conan/data/paho-mqtt-cpp/1.0.1/_/_/package/de1bbfb8eed70320d3c37ce9521ac7e673c69477/include/mqtt/thread_queue.h:318:55: note: add explicit ‘this’ or ‘*this’ capture

[fpagliughi]

I've been resistant to push this library forward into the new standards until they stabilize, but the fix to this seems better and more explicit that what's there now, so it seems worth adding sooner than later.

[fpagliughi]

Apologies that I didn't get this into the new release. I'm going to start looking into C++20 now that it's "official" and probably do a point release (v1.2.1) to address any issues like this.

[fpagliughi]

Fixed this. We can add any other ones that pop up to #340