Question

Linux

I have two functions: functionA and functionB

These two functions can be ran multithreaded, which:

1. There is at most one functionA can be ran at a time
2. There may be many functionB(s) can be ran at a time
3. functionA and functionB are exclusive, i.e if functionA is being excuted
   then functionB must wait until functionA finishes, and if there is any instance of functionB
   is being executed then functionA must wait until all instances of functionB finish.

Could you please show me how to implement this using pthread in Linux? I tried many ways but it seems not clear enough.

Windows

How would I accomplish the same thing in Windows using C++?

Answer 1

You can use boost to create a read-write lock:

#include <boost/thread/locks.hpp>

typedef boost::shared_mutex Lock;
typedef boost::unique_lock< boost::shared_mutex > WrtieLock;
typedef boost::shared_lock< boost::shared_mutex >  ReadLock;

Lock myLock;


void ReadFunction()
{
    ReadLock r_lock(myLock);
    //Do reader stuff
}

void WriteFunction()
{
     WriteLock w_lock(myLock);
     //Do writer stuff
}