C ++ concurrent programming real - Notes

2.1.1

One thing to note, when the function object passed to the constructor of the thread, it is necessary to avoid "the most vexing parsing" (C ++ 's most vexing parse, Chinese Introduction). If you pass a temporary variable instead of a variable named; C ++ compiler will parse function declaration, rather than defining the type of object .
For example:
std :: the Thread my_thread (background_task ()); //

Here is quite a statement with a function called my_thread of this function with a parameter (function has no parameters and returns a pointer to a function background_task object), function returns a std :: thread object, rather than start a thread. Use a named function object in front, or the use of multiple sets of brackets ①, or use the new unified initialization syntax ②, to avoid this problem. Using lambda expression can avoid this problem.
As follows:
STD :: Thread my_thread ((background_task ())); //. 1

std::thread    my_thread{background_task()};                //    2
 

2.2

The default parameters to be copied to a separate thread in memory, even if the parameter is a reference to the form, and can be accessed in the new thread

void    f(int    i,    std::string    const&    s); 
std::thread    t(f,    3,    "hello");

char	buffer[1024];	//	1		
sprintf(buffer,	"%i",some_param);
std::thread	t(f,3,buffer);	//	2
t.detach();

std::thread	t(f,3,std::string(buffer));//使用std::string，避 免悬垂指针