[Stk] Beginners question using RtMidi

[Robert Gründler]

Hi,

i'm having troubles implementing the RtMidiCallback function to process 
incoming midi messages.
I'ts a beginners mistake i assume, i'm getting a linker error:

midi_in.cpp:37: undefined reference to `call_back(double, 
std::vector<unsigned char, std::allocator<unsigned char> >*, void*)'

Here's the code:

#include <iostream>
#include "RtMidi.h"
#include <signal.h>
#include <vector>

using namespace std;

void call_back(double timeStamp, std::vector <unsigned char> *message, 
void *userData) ;

int main( int argc, char *argv[] ) {

RtMidiIn *midi_in = 0;

try {
    midi_in = new RtMidiIn();
}

catch ( RtError& error ) {
    error.printMessage();
    exit(0);
}
midi_in->openPort(1);
midi_in->setCallback(&call_back);
  
delete midi_in;

return 0;
}

Here's how my makefile looks like:

### STK examples Makefile - for various flavors of unix

PROGRAMS = tester midi_in
RM = /bin/rm
SRC_PATH = ../../src
OBJECT_PATH = /usr/lib/
vpath %.o $(OBJECT_PATH)

INCLUDE =
ifeq ($(strip $(INCLUDE)), )
    INCLUDE = /usr/include/
endif
vpath %.h $(INCLUDE)

CC       = g++
DEFS     = -D__LITTLE_ENDIAN__
DEFS    +=
CFLAGS   = -O3
CFLAGS  += -Wall -g -D__GXX__ -I$(INCLUDE)
LIBRARY =  -ljack   -lasound -lpthread -lm  -lasound
LIBRARY +=

REALTIME = yes
ifeq ($(REALTIME),yes)
    DEFS    += -D__LINUX_JACK__ -D__LINUX_ALSASEQ__
endif

RAWWAVES =
ifeq ($(strip $(RAWWAVES)), )
    RAWWAVES = ../../rawwaves/
endif
DEFS    += -DRAWWAVE_PATH=\"$(RAWWAVES)\"

%.o : $(SRC_PATH)/%.cpp
    $(CC) $(CFLAGS) $(DEFS) -c $(<) -o $(OBJECT_PATH)/$@

all : $(PROGRAMS)

$(OBJECTS) : Stk.h

clean :
    -rm $(PROGRAMS)

strip :
    strip $(PROGRAMS)

tester:   test.cpp
    $(CC) $(CFLAGS) test.cpp  -o tester -lstk -ljack -lasound
   
midi_in:   midi_in.cpp
    $(CC) $(CFLAGS) midi_in.cpp -o midi_in -lstk -ljack -lasound  
-lpthread -lm -lasound
 

Any help would be greatly appreciated!

-robert