I have this problem: i want to create a midi synthesizer in C,linux. Since I don't have a USB midi keyboard, I thought about using a virtual midi divice like VMPK. I found this code in a book that also explained how to use the portmidi library:
#include <stdio.h>
#include <portmidi.h>
#include <porttime.h>
int main() {
int cnt,i,dev;
PmError retval;
const PmDeviceInfo *info;
PmEvent msg[32];
PortMidiStream *mstream;
Pm_Initialize();
cnt = Pm_CountDevices();
if(cnt) {
for(i=0; i < cnt; i++){
info = Pm_GetDeviceInfo(i);
if(info->input)
printf("%d: %s \n", i, info->name);
}
printf("choose device: ");
scanf("%d", &dev);
Pt_Start(1, NULL, NULL);
retval = Pm_OpenInput(&mstream, dev, NULL, 512L, NULL,NULL);
if(retval != pmNoError)
printf("error: %s \n", Pm_GetErrorText(retval));
else {
while(Pt_Time(NULL) < 60000){
if(Pm_Poll(mstream)) {
cnt = Pm_Read(mstream, msg, 32);
for(i=0; i<cnt; i++) {
printf("status:%d, byte1=%d, "
"byte2=%d, time=%.3f\n",
Pm_MessageStatus(msg[i].message),
Pm_MessageData1(msg[i].message),
Pm_MessageData2(msg[i].message),
msg[i].timestamp/1000.);
}
}
}
}
Pm_Close(mstream);
}
}
else printf("No MIDI devices found\n");
Pm_Terminate();
return 0;
}
In short, once the program connects with a MIDI input device, it listens for 60 all the messages that come from them, (Printing the status byte and the two data bytes, as a midi protocol)
When I launch VMPK, it appears that the program reveals VMPK as midi input, under the name "out" Program output I also checked the "JACK audio connection" program to verify that VMPK was revealed as a MIDI input device JACK audio output
I don't understand why when I press a key from the VMPK keyboard, I don't receive any messages from the program ...
I tried to change the VMPK configuration, but I didn't get any changes.
Maybe I'm doing something wrong in the VMPK configuration.
Any help is welcome.
I thank you in advance for your availability
