Hey,

I am currently working on a project in which I am using python to communicate with a c++ program. I need to perform a sequence of reads and writes via pipes.

All the examples I've seen are follow the following structure:-
Open two way pipe
write to pipe
close write end
read from pipe
close read end

I don't want to close the write or read end since I will need to send further data later. If I don't close the write end the program hangs. Is this due to the way pipes work? What is the normal solution in this case, do I need to open a new pipe?

In my case I am using python with the following pipe command
fout, fin = os.popen2("./a.out", "t")

Any help would be much appreciated :-)

It is because the other program is most likely waiting for input (or an EOF when you close your end). What program is this, and how is its input buffered?

Yes you were right, one of the processes was waiting for input and so it was hanging. I found that in this situation I needed to use the flush() member function and signal the other process to stop waiting for input.

Not having had much experience with pipes other than the usual console tricks I thought I'd ask about the principles involved for multiple writes and reads. Since there aren't many examples of this.

Python is being used for all the file handling, its then passing this data to a C++ app. Its just some string outputs onto the pipe, another process is reading this data.

Thanks for the input very helpful!