title: What should I do for recieving when the number of send messages is unknown in MPI?
body: <p>I am programming in MPI. I want to send something to another processor and receive it there, but I don't know how many messages I will send. In fact, the number of messages which send to the other processor depends on the file which I am reading it during the program, so I don't know how many receives I should write on the other side. Which method and which function should I use?</p>