I have to develop a multithreaded application, where there will be multiple threads, each thread generates custom event log which need to be saved in queue (not Microsoft MS
What you are planning is a classic producer consumer queue with a thread consuming the items on the queue to do some work. This can be wrapped into is a higher level construct called an "actor" or "active object".
Basically this wraps the queue and the thread that consumes the items into a single class, the other threads all asynchronous methods on this class with put the messages on the queue to be performed by the actor's thread. In your case the class could have a single method writeData which stores the data in the queue and triggers the condition variable to notify the actor thread that there is something in the queue. The actor thread sees if there is any data in the queue if not waits on the condition variable.
Here is a good article on the concept:
http://www.drdobbs.com/go-parallel/article/showArticle.jhtml;jsessionid=UTEXJOTLP0YDNQE1GHPSKH4ATMY32JVN?articleID=225700095