Your link command line is wrong, try this one instead:
gcc -o simple_client simple_client.c `pkg-config --cflags --libs jack`
The order of archive libraries on command line matters.
Frage
I'm trying to follow this introductory tutorial on jack (audio server for linux). In the tutorial, the author explains that you should use pkg-config
to find the cflags
and libs
for jack, making the gcc
command like this:
gcc -o simple_client `pkg-config --cflags --libs jack` simple_client.c
which gives the output:
/tmp/ccyuOC0u.o: In function `signal_handler':
simple_client.c:(.text+0x16): undefined reference to `jack_client_close'
/tmp/ccyuOC0u.o: In function `process':
simple_client.c:(.text+0x6f): undefined reference to `jack_port_get_buffer'
simple_client.c:(.text+0x87): undefined reference to `jack_port_get_buffer'
/tmp/ccyuOC0u.o: In function `main':
simple_client.c:(.text+0x25b): undefined reference to `sin'
simple_client.c:(.text+0x2c1): undefined reference to `jack_client_open'
simple_client.c:(.text+0x372): undefined reference to `jack_get_client_name'
simple_client.c:(.text+0x3b1): undefined reference to `jack_set_process_callback'
simple_client.c:(.text+0x3ca): undefined reference to `jack_on_shutdown'
simple_client.c:(.text+0x3ee): undefined reference to `jack_port_register'
simple_client.c:(.text+0x419): undefined reference to `jack_port_register'
simple_client.c:(.text+0x475): undefined reference to `jack_activate'
simple_client.c:(.text+0x4c5): undefined reference to `jack_get_ports'
simple_client.c:(.text+0x514): undefined reference to `jack_port_name'
simple_client.c:(.text+0x52c): undefined reference to `jack_connect'
simple_client.c:(.text+0x56e): undefined reference to `jack_port_name'
simple_client.c:(.text+0x586): undefined reference to `jack_connect'
simple_client.c:(.text+0x5ba): undefined reference to `jack_free'
collect2: ld returned 1 exit status
I'm not very experienced using gcc or writing c programs generally (most of my experience has been with javascript, clojure, java, python, and php). What I gather from this and my research into it is that some libraries are missing or linked incorrectly (not sure which).
So just running pkg-config --cflags --libs jack
on my machine, I get:
-ljack
In the tutorial referenced above, the author demonstrates the same method for gleaning the libs to be linked for jack, but his output looks like this:
-ljack -lpthread -ldl -lrt
Not sure what pthread is, but I think dl is dsp-loader, and rt has something to do with realtime. I've searched in several directories called /lib
and haven't come across anything for these other libs, so I don't think they exist on my machine. However, it seems strange to me that calling pkg-config
doesn't make any mention of them. How should I go about finding these libs? Or am I on the wrong track?
Lösung
Your link command line is wrong, try this one instead:
gcc -o simple_client simple_client.c `pkg-config --cflags --libs jack`
The order of archive libraries on command line matters.