basic rawmidi_read

Makefile

@@ -4,7 +4,7 @@ exe = housic
 src = $(wildcard *.c)
 obj = $(src:.c=.o)
 
-LDFLAGS = 
+LDFLAGS = -lasound
 
 $(exe): $(obj)
 	$(CC) -o $@ $^ $(LDFLAGS)

main.c

@@ -5,7 +5,56 @@
  * Dedicated to seleomlivet
  *
  */
+#include <alsa/asoundlib.h>
+
+// function declarations:
+void alsa_error(const char *format, ...);
+
 int main(int argc, char *argv[]) {
+  int status;
+  int mode = SND_RAWMIDI_SYNC;
+  snd_rawmidi_t* midiin = NULL;
+  const char* portname = "virtual";
+
+  if ((status = snd_rawmidi_open(&midiin, NULL, portname, mode)) < 0) {
+    alsa_error("Problem opening MIDI input: %s", snd_strerror(status));
+    exit(1);
+  }
+
+  int i = 0;
+  char buffer[3];
+  unsigned char message[3];
+
+  while (1) {
+    if ((status = snd_rawmidi_read(midiin, buffer, 3)) < 0) {
+      alsa_error("Problem reading MIDI input: %s", snd_strerror(status));
+    }
+
+    // in case of MIDI running status, value bytes need to not override status byte
+    for (i=1; i<=status;i++) {
+      message[3-i] = (unsigned char) buffer[status-i];
+    }
+
+    printf("%d: %x %x %x\n", status, message[0], message[1], message[2]);
+    fflush(stdout);
+  }
+
+  snd_rawmidi_close(midiin);
+  midiin=NULL;
   
   return 0;
 }
+
+
+//////////////////////////////
+//
+// error -- print error message
+//
+
+void alsa_error(const char *format, ...) {
+   va_list ap;
+   va_start(ap, format);
+   vfprintf(stderr, format, ap);
+   va_end(ap);
+   putc('\n', stderr);
+}