编译共享库时链接错误

时间:2017-01-16 23:32:06

标签: c linker shared-libraries ctypes libusb

我正在尝试将第三方代码编译到共享库,因此我可以使用ctypes从Python调用它。这是我第一次有意识地使用共享库。

我使用以下方法构建目标代码:

gcc -c -fPIC -o elisa3-lib.o ../elisa3-lib.c   
gcc -c -fPIC -o usb-comm.o ../usb-comm.c

然后我尝试构建共享库:

gcc -shared -fPIC -Wl,-install_name,libelisa3.so -o libelisa3.so.1.0 elisa3-lib.o usb-comm.o -lc

我得到了链接器错误,因为usbcomm.c引用了libusb.h:

#ifdef __APPLE__
    #include </opt/local/include/libusb-1.0/libusb.h>
#endif

有错误:

Undefined symbols for architecture x86_64:
  "_libusb_bulk_transfer", referenced from:
      _usb_send in usb-comm.o
      _usb_receive in usb-comm.o
  "_libusb_claim_interface", referenced from:
      _openCommunication in usb-comm.o
  "_libusb_close", referenced from:
      _closeCommunication in usb-comm.o
  "_libusb_exit", referenced from:
      _closeCommunication in usb-comm.o
  "_libusb_init", referenced from:
      _openCommunication in usb-comm.o
  "_libusb_open_device_with_vid_pid", referenced from:
      _find_nrf_device in usb-comm.o
  "_libusb_release_interface", referenced from:
      _closeCommunication in usb-comm.o
ld: symbol(s) not found for architecture x86_64

如何正确链接?我是否还需要将libusb编译为共享库并与-l?

链接

1 个答案:

答案 0 :(得分:1)

“未定义的符号”是链接器无法找到的函数/变量。简而言之,是的,您需要将libusb作为您链接的库或对象之一。包括哪个更容易或更合适。