[LAD] Problem with small ALSA rawmidi app

Hi, I am trying to communicate with a "real" MIDI device through the ALSA RawMidi API, but it doesn't quite do what I want. I want to: - Send a small SysEx package that asks a device for some data - Receive the answer What I basically do is (code excerpt / pseudo code): snd_rawmidi_t *handle_in = 0, *handle_out = 0; unsigned char ibuf[256]; unsigned char obuf[] = { 0xf0, .., 0xf7 }; /* 6 bytes sysex */ snd_rawmidi_open(&handle_in, NULL, "hw:2,0,0", SND_RAWMIDI_NONBLOCK); snd_rawmidi_open(NULL, &handle_out, "hw:2,0,0", SND_RAWMIDI_NONBLOCK); snd_rawmidi_write(handle_out, &obuf, 6); snd_rawmidi_drain(handle_out); // wait a little for the answer // I know I should not do it this way, but for testing purposes.. usleep(1000000); num = snd_rawmidi_read(handle_in, ibuf, sizeof(ibuf)); I know that the data is sent out, but reading back the answer always gives me -1 for num. Trying to do the same thing with 2 instances of the "amidi" program works, though: First terminal window: amidi -p hw:2,0,0 -d Second terminal window: amidi -p hw:2,0,0 -S "F0.....F7" Sending the second one out, I immediately get the desired answer on the first terminal. I'm sure there is something very basic I am doing wrong, but I fail to see that at the moment. Eventually, the whole thing will have to be rewritten for the ALSA sequencer API anyway, but for a first quick test, I wanted to try it this way. Any hints are most welcome. Thanks, Frank