I'd like python to send around a half-million integers in the range 0-255 each to an executable written in C++. This executable will then respond with a few thousand integers. Each on one line. This seems like it should be very simple to do with subprocess but i've had endless troubles. Right now im testing with code:

// main()
u32 num;
std::cin >> num;

u8* data = new u8[num];
for (u32 i = 0; i < num; ++i)
    std::cin >> data[i];

// test output / spit it back out
for (u32 i = 0; i < num; ++i)
    std::cout << data[i] << std::endl;

return 0;

Building an array of strings ("data"), each like "255\n", in python and then using:

output = proc.communicate("".join(data))[0]

...doesn't work (says stdin is closed, maybe too much at one time). Neither has using proc.stdin and proc.stdout worked. This should be so very simple, but I'm getting constant exceptions, and/or no output data returned to me. My Popen is currently:

proc = Popen('aux/test_cpp_program', stdin=PIPE, stdout=PIPE, bufsize=1)

Advise me before I pull my hair out. ;)