James Zappia said:

Hi,

I'm a newbie to C++ and Boost and I'm trying to port a threaded C program I have to Boost.Threads. I'm trying to use scoped_try_lock to test a lock on mutex and it's not working. I'm obviously doing something wrong but I can't figure it out. Below is the source code. Any help would be greatly appreciated.

How is it not working? What do you expect to happen?

SOURCE:

#include <iostream> #include #include

using namespace std;

boost::try_mutex mutex;

void thread_test( void ) { cout << "thread: locking mutex\n";

{ boost::try_mutex::scoped_try_lock lock(mutex); cout << "thread: sleeping for 10 seconds\n"; sleep(10); }

cout << "thread: unlocked mutex - goodbye!\n";

return; }

int main( void ) { cout << "main: creating thread\n"; boost::thread thread(thread_test);

cout << "main: sleeping for 2 seconds\n"; sleep(2);

cout << "main: trying to lock mutex\n"; boost::try_mutex::scoped_try_lock lock(mutex,true);

This will force a lock (which means we'll block until the thread releases the lock).

while ( !lock.try_lock() )

Since the above insured the mutex is already locked, this would be a recursive lock which should result in a thread_lock_error exception being thrown. Is this not what's happening for you?

cout << "main: retrying to lock mutex\n";

cout << "main: joining thread\n"; thread.join();

cout << "main: thread joined\n"; return 0; }

William E. Kempf