在Linux上链接c ++库

Question

我正在运行以下命令：

g++ -m32 testLogin.cpp  -L/root/c++/libs  -ldvrnetsdk -o testLoginO -lpthread  -lasound 

结果：

/root/c++/libs/libdvrnetsdk.so: undefined reference to `snd_pcm_hw_params_set_channels'
/root/c++/libs/libdvrnetsdk.so: undefined reference to `pthread_mutex_trylock'
/root/c++/libs/libdvrnetsdk.so: undefined reference to `snd_pcm_readi'
/root/c++/libs/libdvrnetsdk.so: undefined reference to `snd_pcm_hw_params_set_access'
/root/c++/libs/libdvrnetsdk.so: undefined reference to `snd_strerror'
/root/c++/libs/libdvrnetsdk.so: undefined reference to `pthread_mutexattr_settype'
/root/c++/libs/libdvrnetsdk.so: undefined reference to `snd_pcm_hw_params_set_rate'
/root/c++/libs/libdvrnetsdk.so: undefined reference to `snd_pcm_close'
/root/c++/libs/libdvrnetsdk.so: undefined reference to `snd_pcm_hw_params_malloc'
/root/c++/libs/libdvrnetsdk.so: undefined reference to `snd_pcm_hw_params_set_period_size'
/root/c++/libs/libdvrnetsdk.so: undefined reference to `pthread_mutex_timedlock'
/root/c++/libs/libdvrnetsdk.so: undefined reference to `pthread_mutexattr_destroy'
/root/c++/libs/libdvrnetsdk.so: undefined reference to `snd_pcm_drain'
/root/c++/libs/libdvrnetsdk.so: undefined reference to `snd_pcm_hw_params_free'
/root/c++/libs/libdvrnetsdk.so: undefined reference to `pthread_create'
/root/c++/libs/libdvrnetsdk.so: undefined reference to `snd_pcm_open'
/root/c++/libs/libdvrnetsdk.so: undefined reference to `snd_pcm_hw_params_set_format'
/root/c++/libs/libdvrnetsdk.so: undefined reference to `snd_pcm_writei'
/root/c++/libs/libdvrnetsdk.so: undefined reference to `pthread_mutexattr_init'
/root/c++/libs/libdvrnetsdk.so: undefined reference to `snd_pcm_hw_params'
/root/c++/libs/libdvrnetsdk.so: undefined reference to `snd_pcm_hw_params_any'
/root/c++/libs/libdvrnetsdk.so: undefined reference to `snd_pcm_prepare'
/root/c++/libs/libdvrnetsdk.so: undefined reference to `pthread_join'
collect2: error: ld returned 1 exit status

发生此错误后，我要做的第一件事是包括库-lpthread -lasound，我也处理了参数order，但没有工作。 我寻求任何帮助。

Answer 1

您是否尝试仅使用-pthread作为链接器标志...有时不使用-lpthread ...

这应该工作

g ++ -m32 testLogin.cpp -L / root / c ++ / libs -ldvrnetsdk -pthread -lasound

Answer 2

使用gcc，链接的顺序很重要。

因此，尝试使用不同的顺序。

 g++ -m32 testLogin.cpp  -L/root/c++/libs -lpthread -lasound -ldvrnetsdk -o testLoginO

有关顺序的信息，请参见以下问题： 为什么链接库的顺序有时会导致GCC错误？

或者，您可以使用开始组选项。

gcc -m32 testLogin.cpp  -L/root/c++/libs -Wl,--start-group -lpthread -lasound -ldvrnetsdk -Wl,--end-group -o testLoginO

编辑：当您仍然收到错误时，请对库上的字符串使用nm并检查库中是否给出了给出链接器错误的符号。 检查库版本。 您可能在64位内核上。