Question

In pthread_create I can specify one message, then on run time I may get new messages that need to be passed to the thread for printing.

One way may be to create a global vector, and keep on adding messages to it. The thread will fetch that vector and scan it for new messages.
But in this way n vectors will have to be created for n threads!
Or one structure with threadid, message, and print status.

What are the possible practical ways out?

EDIT 1:

Is the following design fine or needs some improvements?

The following code will be written in a normal function which will be called by main().

• Check if the thread (responsible for grabbing that message) is already there.

  • If yes, Push the message in that thread’s queue, wake up the thread with (pthread_cond_signal()).
  • If no, create the thread, create its queue, push the message in that queue.

• When the thread finishes reading all the messages in its queue, let it to sleep with (pthread_cond_wait()).

Answer 1

Google ‘pthreads producer consumer queue’. You should not need to scan for new entries – the producer/s signal the consumer thread that new entries are available.