tf::ObserverInterface tf::ChromeObserver tf::TFProfObserver taskflow/core/observer.hpp virtual tf::ObserverInterface::~ObserverInterface ()=default ~ObserverInterface virtual destructor void virtual void tf::ObserverInterface::set_up (size_t num_workers)=0 set_up set_up set_up size_t num_workers constructor-like method to call when the executor observer is fully created num_workers the number of the worker threads in the executor void virtual void tf::ObserverInterface::on_entry (WorkerView wv, TaskView task_view)=0 on_entry on_entry on_entry WorkerView wv TaskView task_view method to call before a worker thread executes a closure wv an immutable view of this worker thread task_view a constant wrapper object to the task void virtual void tf::ObserverInterface::on_exit (WorkerView wv, TaskView task_view)=0 on_exit on_exit on_exit WorkerView wv TaskView task_view method to call after a worker thread executed a closure wv an immutable view of this worker thread task_view a constant wrapper object to the task class to derive an executor observer The tf::ObserverInterface class allows users to define custom methods to monitor the behaviors of an executor. This is particularly useful when you want to inspect the performance of an executor and visualize when each thread participates in the execution of a task. To prevent users from direct access to the internal threads and tasks, tf::ObserverInterface provides immutable wrappers, tf::WorkerView and tf::TaskView, over workers and tasks. Please refer to tf::WorkerView and tf::TaskView for details. Example usage: structMyObserver:publictf::ObserverInterface{ MyObserver(conststd::string&name){ std::cout<<"constructingobserver"<<name<<'\n'; } voidset_up(size_tnum_workers)overridefinal{ std::cout<<"settingupobserverwith"<<num_workers<<"workers\n"; } voidon_entry(WorkerVieww,tf::TaskViewtv)overridefinal{ std::ostringstreamoss; oss<<"worker"<<w.id()<<"readytorun"<<tv.name()<<'\n'; std::cout<<oss.str(); } voidon_exit(WorkerVieww,tf::TaskViewtv)overridefinal{ std::ostringstreamoss; oss<<"worker"<<w.id()<<"finishedrunning"<<tv.name()<<'\n'; std::cout<<oss.str(); } }; tf::Taskflowtaskflow; tf::Executorexecutor; //inserttasksintotaskflow //... //createacustomobserver std::shared_ptr<MyObserver>observer=executor.make_observer<MyObserver>("MyObserver"); //runthetaskflow executor.run(taskflow).wait(); tf::ObserverInterface tf::ChromeObserver tf::TFProfObserver tf::ObserverInterfaceon_entry tf::ObserverInterfaceon_exit tf::ObserverInterfaceset_up tf::ObserverInterface~ObserverInterface