How to detect that there is a pending message need to be received?

[Former user]

Is there a way to detect there will be a pending message need to be received?

For example, I want to receive multiple messages from other cores, but I don`t know the number of messages. How can I do before using ireceive?

[Lisandro Dalcin]

In MPI, you can check just one message at a time using pending = comm.Iprobe(MPI.ANY_SOURCE). You can pass an additional MPI.Status object to get back the actual source of the sender form status.Get_source(). This is just the MPI way of doing things.

PS: General questions like this one are more appropriate for our mailing list.