无法从google协议缓冲区编译示例

Question

我搜索其他主题，但它们对我没有帮助=（。在我的工作服务器上，我没有sudo特权，所以我安装PB时使用

./配置--prefix=/home/用户名/本地

然后我用“人”例子创建源文件，并用协议成功编译。

我没有pkg信息=（。我尝试用

g-I/home/username/local/include-L/home/username/local/lib-lprotobuf-lpthread main。cpp人员。pb。复写的副本

然后有10亿个模拟误差，即。

人pb。cc:（.text 0x4cf）：对“google:：protobuf:：internal:：kEmptyString”的未定义引用

我认为，这是链接的问题，但如何解决呢？

echo$LD\u LIBRARY\u路径/主页/用户名/本地/库

在main.cpp：

#include "person.pb.h"
...

谢谢。

Answer 1

还有一个相当普遍的问题，它不仅适用于链接protobuf，还适用于其他库。既然这是我的问题，我会把解决方案放在这里，也许有人会觉得它有用。

确保您正在尝试链接到具有相同ABI的库。C ABI在GCC 4.7.0中已更改。因此，您无法链接使用GCC编译的库

这个问题可以通过planty linkage抱怨std：：basic\u string和std：：list来识别，因为这是C中最有前途的ABI更改。我的链接器尖叫如下：

    /bincrafters/stable/package/c0c1ef10e3d0ded44179e28b669d6aed0277ca6a/lib  -L/home/adam/.conan/data/libpcap/1.8.1/bincrafters/stable/package/0a813c597d519ec14c71192b99d7de0a92bbc1c3/lib  -L/home/adam/.conan/data/zmq/4.2.2/bincrafters/stable/package/0144a3b0aceb8edb5e63295c432a8de8020ab1b7/lib  -L/home/adam/.conan/data/libsodium/1.0.16/bincrafters/stable/package/db2ca884c9793e0b0fb54ec3f846326d1addacc8/lib -Wl,-rpath,/hoar, std::char_traits<char>, std::allocator<char> > const&, google::protobuf::io::CodedOutputStream*)'
CMakeFiles/NetworkMonitor.dir/addressbook.pb.cc.o: In function `tutorial::Person_PhoneNumber::InternalSerializeWithCachedSizesToArray(unsigned char*) const':
/home/adam/.conan/data/protobuf/3.9.1/bincrafters/stable/package/053ea29eb0edc6b1695c893b738a971110c756fd/include/google/protobuf/wire_format_lite.h:1673: undefined reference to `google::protobuf::io::CodedOutputStream::WriteStringWithSizeToArray(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, unsigned char*)'
/home/adam/.conan/data/protobuf/3.9.1/bincrafters/stable/package/053ea29eb0edc6b1695c893b738a971110c756fd/include/google/protobuf/wire_format_lite.h:1673: undefined reference to `google::protobuf::io::CodedOutputStream::WriteStringWithSizeToArray(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, unsigned char*)'
CMakeFiles/NetworkMonitor.dir/addressbook.pb.cc.o: In function `google::protobuf::internal::GetEmptyStringAlreadyInited[abi:cxx11]()':
/home/adam/.conan/data/protobuf/3.9.1/bincrafters/stable/package/053ea29eb0edc6b1695c893b738a971110c756fd/include/google/protobuf/message_lite.h:153: undefined reference to `google::protobuf::internal::fixed_address_empty_string[abi:cxx11]'
CMakeFiles/NetworkMonitor.dir/addressbook.pb.cc.o: In function `google::protobuf::internal::WireFormatLite::ReadString(google::protobuf::io::CodedInputStream*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*)':
/home/adam/.conan/data/protobuf/3.9.1/bincrafters/stable/package/053ea29eb0edc6b1695c893b738a971110c756fd/include/google/protobuf/wire_format_lite.h:880: undefined reference to `google::protobuf::internal::WireFormatLite::ReadBytes(google::protobuf::io::CodedInputStream*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*)'
CMakeFiles/NetworkMonitor.dir/addressbook.pb.cc.o:(.data.rel.ro._ZTVN8tutorial11AddressBookE[_ZTVN8tutorial11AddressBookE]+0x20): undefined reference to `google::protobuf::Message::GetTypeName[abi:cxx11]() const'
CMakeFiles/NetworkMonitor.dir/addressbook.pb.cc.o:(.data.rel.ro._ZTVN8tutorial11AddressBookE[_ZTVN8tutorial11AddressBookE]+0x58): undefined reference to `google::protobuf::Message::InitializationErrorString[abi:cxx11]() const'
CMakeFiles/NetworkMonitor.dir/addressbook.pb.cc.o:(.data.rel.ro._ZTVN8tutorial6PersonE[_ZTVN8tutorial6PersonE]+0x20): undefined reference to `google::protobuf::Message::GetTypeName[abi:cxx11]() const'
CMakeFiles/NetworkMonitor.dir/addressbook.pb.cc.o:(.data.rel.ro._ZTVN8tutorial6PersonE[_ZTVN8tutorial6PersonE]+0x58): undefined reference to `google::protobuf::Message::InitializationErrorString[abi:cxx11]() const'
CMakeFiles/NetworkMonitor.dir/addressbook.pb.cc.o:(.data.rel.ro._ZTVN8tutorial18Person_PhoneNumberE[_ZTVN8tutorial18Person_PhoneNumberE]+0x20): undefined reference to `google::protobuf::Message::GetTypeName[abi:cxx11]() const'
make[2]: *** [bin/N

在我为conan定义了一个概要文件并链接到使用相同版本的C ABI编译的库之后，这个问题就消失了。

Answer 2

库链接标志位于编译器参数的末尾：

g-I/home/username/local/include-L/home/username/local/lib main。cpp人员。pb。cc-lprotobuf-lpthread

Answer 3

将库放在末尾：

/home/username/local/include /home/username/local/libperson.pb.cc

从GCC链接选项：

-llibrary
-l library
    Search the library named library when linking. 
    (The second alternative with the library as a separate argument
    is only for POSIX compliance and is not recommended.)

    It makes a difference where in the command you write this option;
    the linker searches and processes libraries and object files in the
    order they are specified.
    Thus, `foo.o -lz bar.o' searches library `z' after file foo.o but
    before bar.o. If bar.o refers to functions in `z', those functions
    may not be loaded.

此外，使用pthread而不是lpthread，因为pthread可以为预处理器和链接器设置标志。