api-reference/call_once_8hpp_source.html

 #ifndef INCLUDE_DISTORTOS_CALLONCE_HPP_
 #define INCLUDE_DISTORTOS_CALLONCE_HPP_

 #include "distortos/internal/CHECK_FUNCTION_CONTEXT.hpp"

 #include "distortos/OnceFlag.hpp"

 #include "estd/invoke.hpp"

 #include <mutex>

 namespace distortos
 {

 template<typename Function, typename... Args>
 void callOnce(OnceFlag& onceFlag, Function&& function, Args&&... args)
 {
     CHECK_FUNCTION_CONTEXT();

     if (onceFlag.done_ == true)
         return;

     const std::lock_guard<Mutex> lockGuard {onceFlag.mutex_};

     if (onceFlag.done_ == true)
         return;

     estd::invoke(std::forward<Function>(function), std::forward<Args>(args)...);
     onceFlag.done_ = true;
 }

 }   // namespace distortos

 #endif  // INCLUDE_DISTORTOS_CALLONCE_HPP_
CHECK_FUNCTION_CONTEXT.hpp
CHECK_FUNCTION_CONTEXT() macro.

distortos::OnceFlag::mutex_
Mutex mutex_
internal mutex used by callOnce()
Definition: OnceFlag.hpp:50

OnceFlag.hpp
OnceFlag class header.

distortos::callOnce
void callOnce(OnceFlag &onceFlag, Function &&function, Args &&... args)
Executes the callable object exactly once, even if called from multiple threads.
Definition: callOnce.hpp:45

distortos
Top-level namespace of distortos project.
Definition: buttons.hpp:33

CHECK_FUNCTION_CONTEXT
#define CHECK_FUNCTION_CONTEXT()
Macro used to check whether the function is executed from thread context.
Definition: CHECK_FUNCTION_CONTEXT.hpp:29

distortos::OnceFlag::done_
volatile bool done_
tells whether any function was already called for this object (true) or not (false)
Definition: OnceFlag.hpp:53

estd::invoke
auto invoke(Function &&function, Args &&... args) -> decltype(internal::invoke(std::forward< Function >(function), std::forward< Args >(args)...))
Invokes callable object in an appropriate way.
Definition: invoke.hpp:139

distortos::OnceFlag
OnceFlag is a helper class for callOnce().
Definition: OnceFlag.hpp:29

invoke.hpp
invoke() header