Thread: libusb: unable to compile

I am trying to compile a program that uses libusb. It is going to interface with the microsoft xbox on a board that uses a TI Omap processor. I am getting the following undefined references and I am not too sure what to do from the messages I am getting.

Code:

arm-none-linux-gnueabi-gcc -o kinectTestTry1 usb_libusb10.c
/root/CodeSourcery/Sourcery_G++_Lite/bin/../arm-none-linux-gnueabi/libc/usr/lib/crt1.o: In function `_start':
init.c:(.text+0x34): undefined reference to `main'
/tmp/cckCeRjr.o: In function `fnusb_num_devices':
usb_libusb10.c:(.text+0x134): undefined reference to `libusb_get_device_list'
usb_libusb10.c:(.text+0x18c): undefined reference to `libusb_get_device_descriptor'
usb_libusb10.c:(.text+0x1fc): undefined reference to `libusb_free_device_list'
/tmp/cckCeRjr.o: In function `fnusb_init':
usb_libusb10.c:(.text+0x240): undefined reference to `libusb_init'
/tmp/cckCeRjr.o: In function `fnusb_shutdown':
usb_libusb10.c:(.text+0x2dc): undefined reference to `libusb_exit'
/tmp/cckCeRjr.o: In function `fnusb_process_events':
usb_libusb10.c:(.text+0x318): undefined reference to `libusb_handle_events'
/tmp/cckCeRjr.o: In function `fnusb_open_subdevices':
usb_libusb10.c:(.text+0x394): undefined reference to `libusb_get_device_list'
usb_libusb10.c:(.text+0x3f4): undefined reference to `libusb_get_device_descriptor'
usb_libusb10.c:(.text+0x46c): undefined reference to `libusb_open'
usb_libusb10.c:(.text+0x4a0): undefined reference to `fn_log'
usb_libusb10.c:(.text+0x4c4): undefined reference to `libusb_claim_interface'
usb_libusb10.c:(.text+0x4e8): undefined reference to `fn_log'
usb_libusb10.c:(.text+0x4f8): undefined reference to `libusb_close'
usb_libusb10.c:(.text+0x568): undefined reference to `libusb_open'
usb_libusb10.c:(.text+0x59c): undefined reference to `fn_log'
usb_libusb10.c:(.text+0x5c0): undefined reference to `libusb_claim_interface'
usb_libusb10.c:(.text+0x5e4): undefined reference to `fn_log'
usb_libusb10.c:(.text+0x5f4): undefined reference to `libusb_close'
usb_libusb10.c:(.text+0x64c): undefined reference to `libusb_free_device_list'
usb_libusb10.c:(.text+0x698): undefined reference to `libusb_release_interface'
usb_libusb10.c:(.text+0x6a8): undefined reference to `libusb_close'
usb_libusb10.c:(.text+0x6cc): undefined reference to `libusb_release_interface'
usb_libusb10.c:(.text+0x6dc): undefined reference to `libusb_close'
/tmp/cckCeRjr.o: In function `fnusb_close_subdevices':
usb_libusb10.c:(.text+0x738): undefined reference to `libusb_release_interface'
usb_libusb10.c:(.text+0x748): undefined reference to `libusb_close'
usb_libusb10.c:(.text+0x778): undefined reference to `libusb_release_interface'
usb_libusb10.c:(.text+0x788): undefined reference to `libusb_close'
/tmp/cckCeRjr.o: In function `iso_callback':
usb_libusb10.c:(.text+0x828): undefined reference to `fn_log'
usb_libusb10.c:(.text+0x8dc): undefined reference to `libusb_submit_transfer'
usb_libusb10.c:(.text+0x90c): undefined reference to `fn_log'
/tmp/cckCeRjr.o: In function `fnusb_start_iso':
usb_libusb10.c:(.text+0xa30): undefined reference to `fn_log'
usb_libusb10.c:(.text+0xa4c): undefined reference to `libusb_alloc_transfer'
usb_libusb10.c:(.text+0xb08): undefined reference to `libusb_submit_transfer'
usb_libusb10.c:(.text+0xb34): undefined reference to `fn_log'
/tmp/cckCeRjr.o: In function `fnusb_stop_iso':
usb_libusb10.c:(.text+0xbe0): undefined reference to `libusb_cancel_transfer'
usb_libusb10.c:(.text+0xc14): undefined reference to `libusb_handle_events'
usb_libusb10.c:(.text+0xc58): undefined reference to `libusb_free_transfer'
/tmp/cckCeRjr.o: In function `fnusb_control':
usb_libusb10.c:(.text+0xd0c): undefined reference to `libusb_control_transfer'
collect2: ld returned 1 exit status

From what I can collect these are issues with the fact that the compiler can't find the libusb library as I believe these functions are defined there. However I am not too sure how to link the library to the compiler or if this is even what is going on. A little light on the situation can help me tremendously on how to proceed.

Thanks.
-V

You probably need to actually link in the library. Including the header file only gives you declarations, not the actual code. If the library files are something like libusb.a or libusb.so, try using a -lusb (drop the lib prefix and .a/.so extension). Also, if it's not in a standard location for gcc to find, you my need to use the -L option to give it extra paths to search for libraries.