Question

在Ubuntu 14.04上，我正在尝试做一个蓝牙设备列表的小例子，但是在编译这个简约的演示http://people.csail.mit.edu/albert/bluez-intro/c404.html时，我面临一个关于与蓝牙共享库链接的简单问题：

$ sudo apt-get install libbluetooth-dev

$ gcc -lbluetooth simplescan.c -o simplescan
/tmp/ccuwRsB5.o: In function `main':
simplescan.c:(.text+0x79): undefined reference to `hci_get_route'
simplescan.c:(.text+0x8c): undefined reference to `hci_open_dev'
simplescan.c:(.text+0x132): undefined reference to `hci_inquiry'
simplescan.c:(.text+0x18f): undefined reference to `ba2str'
simplescan.c:(.text+0x1f0): undefined reference to `hci_read_remote_name'
collect2: error: ld returned 1 exit status

$ nm -D /usr/lib/x86_64-linux-gnu/libbluetooth.so.3.13.0 | grep hci_get_route
0000000000008f00 T hci_get_route

似乎找到蓝牙共享库并包含所需的功能，但链接阶段无法实现。

Answer 1

解决方案让我感到惊讶（对我来说）：给gcc的参数顺序很重要。 “-lbluetooth”应放在“simplescan.c”之后：

$ gcc simplescan.c -lbluetooth -o simplescan # Success
$ gcc -lbluetooth simplescan.c -o simplescan # Failure
/tmp/ccWhZFXs.o: In function `main':
simplescan.c:(.text+0x79): undefined reference to `hci_get_route'
simplescan.c:(.text+0x8c): undefined reference to `hci_open_dev'
simplescan.c:(.text+0x132): undefined reference to `hci_inquiry'
simplescan.c:(.text+0x18f): undefined reference to `ba2str'
simplescan.c:(.text+0x1f0): undefined reference to `hci_read_remote_name'
collect2: error: ld returned 1 exit status

与libbluetooth.so链接

1 个答案: