Question

I don’t know if more information is needed than the code below, but if more is needed just say so and I will post the remaining code. When compiling I am getting the following error:

g++ -c -pipe -O2 -Wall -W  -I../../../../QtSDK/Desktop/Qt/4.8.0/gcc/mkspecs/linux-g++ -I. -o main.o main.cpp
In file included from main.cpp:4:
TimerManager.h: In function 'void* create_pthread(void*)':
TimerManager.h:17: error: expected nested-name-specifier before 'TimerManager'
TimerManager.h:17: error: expected '(' before 'TimerManager'
TimerManager.h:17: error: expected ';' before 'TimerManager'
make: *** [main.o] Error 1

---

What do I need to change below to get rid of these errors?

---

template<class Object>
void *create_pthread(void *data)
{
  typename TimerManager<Object> *tm = static_cast<TimerManager<Object> *>(data);
  return data;
}

...

template<class CallObject>
class TimerManager {
    ...
};

...

template<class CallObject>
TimerManager<CallObject>::TimerManager() :
  m_bRunning(false),
  m_bGo(false),
  m_lMinSleep(0)
{
  int mutex_creation = pthread_mutex_init(&m_tGoLock, NULL);
  if(mutex_creation != 0) {
    throw TimerManager::TimerError(std::string("Failed to create mutex"));
  }

  int mutex_cond_creation = pthread_cond_init(&m_tGoLockCondition, NULL);
  if(mutex_cond_creation != 0) {
    throw TimerManager::TimerError(std::string("Failed to create condition mutex"));
    return;
  }

  int thread_creation = pthread_create(&m_tTimerThread, NULL, create_pthread<CallObject>, this);
  if(thread_creation != 0) {
    throw TimerManager::TimerError(std::string("Failed to create thread"));
    return;
  }
  m_bRunning = true;
}

Answer 1

I think the problem is that, given the ordering you have of the declarations, the TimerManager class template hasn’t been declared prior to your definition of create_pthread. As a result, the compiler reports an error because TimerManager isn’t in scope. Reordering the functions should fix that.

Also, you don’t need a typename in the line

typename TimerManager<Object> *tm = static_cast<TimerManager<Object> *>(data);

typename is only necessary if you are accessing a nested type inside of TimerManager<Object>. You should be able to remove it without any problems.

Hope this helps!