在 protobuf class 中没有访问或设置值的有效方法
no valid method for accessing or setting values in protobuf class
我最近一直在与 Google protobufs 作斗争。我写了一个名为 Button.proto.
的原型文件
内容如下：
syntax = "proto3";
package robotjoystick;
message Button {
string name = 1;
int32 id = 2;
uint32 state = 3;
}
我用这个命令成功编译了它（用实际计算机用户替换了 $USER）：
protoc -I=/home/$USER/robotjoystickserver --cpp_out=/home/$USER/robotjoystickserver/proto_classes Button.proto
我使用的是 protobuf 版本 3.7.1。
我的 *.cpp 文件名为 dumbprrotos.cpp 并且由于某种原因没有编译。
这是我的 *.cpp 文件：
// Client side C/C++ program to demonstrate Socket programming
#include <stdio.h>
#include <sys/socket.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <string.h>
// This line was forgotten apparently -
#include <arpa/inet.h>
// This one was also forgotten - https://www.reddit.com/r/learnprogramming/comments/3tlii5/clinux_why_is_write_or_close_not_declared_in_this/
#include <unistd.h>
// This is SDL 2.0, the joystick control library
#include <SDL2/SDL.h>
// For Ctrl+C quitting
#include <signal.h>
// for std::end
//#include <iostream>
// Now we import the header files the protobuf compiler generated.
#include "proto_classes/Button.pb.h"
// This is a standard port
#define PORT 8080
//#include<iostream>
using namespace std;
// For the protobuf generated class.
using namespace robotjoystick;
int main(int argc, char const *argv[])
{
// https://developers.google.com/protocol-buffers/docs/cpptutorial
// Verify that the version of the library that we linked against is
// compatible with the version of the headers we compiled against.
GOOGLE_PROTOBUF_VERIFY_VERSION;
// Broken method 1
/*
const string thename = "blah";
robotjoystick::Button * thebutton;
thebutton = new Button();
thebutton->set_name("john");
thebutton->set_id(12);
*/
// Broken method 2
const string thename = "blah";
robotjoystick::Button thebutton;
thebutton.set_name("john");
thebutton.set_id(12);
return 0;
}
我标记的 2 段代码是我试图完成的同一件事的 2 个版本，但都抛出相同类型的错误，我不知道如何解释它。我需要做什么才能编译此代码？
我还应该提到我在我的主目录下安装了 protobuf 3.7.1（这意味着 protobuf 的 zip 文件是在那里提取然后安装在那里）。
当前 运行 代码时出现的错误，确切地说，我收到此错误：
Compiling dumbprotos.cpp
/tmp/cc7HHVQf.o: In function `google::protobuf::internal::GetEmptyStringAlreadyInited[abi:cxx11]()':
dumbprotos.cpp:(.text._ZN6google8protobuf8internal27GetEmptyStringAlreadyInitedB5cxx11Ev[_ZN6google8protobuf8internal27GetEmptyStringAlreadyInitedB5cxx11Ev]+0x5): undefined reference to `google::protobuf::internal::fixed_address_empty_string[abi:cxx11]'
/tmp/ccMdby3z.o: In function `AddDescriptors_Button_2eproto()':
Button.pb.cc:(.text+0xa6): undefined reference to `google::protobuf::internal::AddDescriptors(google::protobuf::internal::DescriptorTable*, void (* const*)(), int)'
/tmp/ccMdby3z.o: In function `robotjoystick::Button::MergePartialFromCodedStream(google::protobuf::io::CodedInputStream*)':
Button.pb.cc:(.text+0x660): undefined reference to `google::protobuf::io::CodedInputStream::ReadTagFallback(unsigned int)'
Button.pb.cc:(.text+0x73f): undefined reference to `google::protobuf::internal::WireFormatLite::VerifyUtf8String(char const*, int, google::protobuf::internal::WireFormatLite::Operation, char const*)'
/tmp/ccMdby3z.o: In function `robotjoystick::Button::SerializeWithCachedSizes(google::protobuf::io::CodedOutputStream*) const':
Button.pb.cc:(.text+0x904): undefined reference to `google::protobuf::internal::WireFormatLite::VerifyUtf8String(char const*, int, google::protobuf::internal::WireFormatLite::Operation, char const*)'
/tmp/ccMdby3z.o: In function `robotjoystick::Button::InternalSerializeWithCachedSizesToArray(unsigned char*) const':
Button.pb.cc:(.text+0xa98): undefined reference to `google::protobuf::internal::WireFormatLite::VerifyUtf8String(char const*, int, google::protobuf::internal::WireFormatLite::Operation, char const*)'
/tmp/ccMdby3z.o: In function `robotjoystick::Button::GetMetadata() const':
Button.pb.cc:(.text+0x1386): undefined reference to `google::protobuf::internal::AssignDescriptors(google::protobuf::internal::AssignDescriptorsTable*)'
/tmp/ccMdby3z.o: In function `robotjoystick::Button* google::protobuf::Arena::CreateMaybeMessage<robotjoystick::Button>(google::protobuf::Arena*)':
Button.pb.cc:(.text+0x142e): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAligned(unsigned long)'
Button.pb.cc:(.text+0x144b): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAlignedAndAddCleanup(unsigned long, void (*)(void*))'
/tmp/ccMdby3z.o: In function `google::protobuf::io::CodedInputStream::ReadVarint32(unsigned int*)':
Button.pb.cc:(.text._ZN6google8protobuf2io16CodedInputStream12ReadVarint32EPj[_ZN6google8protobuf2io16CodedInputStream12ReadVarint32EPj]+0x78): undefined reference to `google::protobuf::io::CodedInputStream::ReadVarint32Fallback(unsigned int)'
/tmp/ccMdby3z.o: In function `google::protobuf::Arena::AllocHook(std::type_info const*, unsigned long) const':
Button.pb.cc:(.text._ZNK6google8protobuf5Arena9AllocHookEPKSt9type_infom[_ZNK6google8protobuf5Arena9AllocHookEPKSt9type_infom]+0x3d): undefined reference to `google::protobuf::Arena::OnArenaAllocation(std::type_info const*, unsigned long) const'
/tmp/ccMdby3z.o: In function `google::protobuf::internal::ArenaStringPtr::CreateInstance(google::protobuf::Arena*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const*)':
Button.pb.cc:(.text._ZN6google8protobuf8internal14ArenaStringPtr14CreateInstanceEPNS0_5ArenaEPKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE[_ZN6google8protobuf8internal14ArenaStringPtr14CreateInstanceEPNS0_5ArenaEPKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE]+0x23e): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAligned(unsigned long)'
Button.pb.cc:(.text._ZN6google8protobuf8internal14ArenaStringPtr14CreateInstanceEPNS0_5ArenaEPKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE[_ZN6google8protobuf8internal14ArenaStringPtr14CreateInstanceEPNS0_5ArenaEPKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE]+0x25b): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAlignedAndAddCleanup(unsigned long, void (*)(void*))'
/tmp/ccMdby3z.o: In function `google::protobuf::internal::InitSCC(google::protobuf::internal::SCCInfoBase*)':
Button.pb.cc:(.text._ZN6google8protobuf8internal7InitSCCEPNS1_11SCCInfoBaseE[_ZN6google8protobuf8internal7InitSCCEPNS1_11SCCInfoBaseE]+0x4d): undefined reference to `google::protobuf::internal::InitSCCImpl(google::protobuf::internal::SCCInfoBase*)'
/tmp/ccMdby3z.o: In function `google::protobuf::internal::OnShutdownDestroyMessage(void const*)':
Button.pb.cc:(.text._ZN6google8protobuf8internal24OnShutdownDestroyMessageEPKv[_ZN6google8protobuf8internal24OnShutdownDestroyMessageEPKv]+0x14): undefined reference to `google::protobuf::internal::DestroyMessage(void const*)'
Button.pb.cc:(.text._ZN6google8protobuf8internal24OnShutdownDestroyMessageEPKv[_ZN6google8protobuf8internal24OnShutdownDestroyMessageEPKv]+0x19): undefined reference to `google::protobuf::internal::OnShutdownRun(void (*)(void const*), void const*)'
/tmp/ccMdby3z.o: In function `google::protobuf::internal::InternalMetadataWithArena::default_instance()':
Button.pb.cc:(.text._ZN6google8protobuf8internal25InternalMetadataWithArena16default_instanceEv[_ZN6google8protobuf8internal25InternalMetadataWithArena16default_instanceEv]+0x5): undefined reference to `google::protobuf::UnknownFieldSet::default_instance()'
/tmp/ccMdby3z.o: In function `google::protobuf::internal::InternalMetadataWithArenaBase<google::protobuf::UnknownFieldSet, google::protobuf::internal::InternalMetadataWithArena>::mutable_unknown_fields_slow()':
Button.pb.cc:(.text._ZN6google8protobuf8internal29InternalMetadataWithArenaBaseINS0_15UnknownFieldSetENS1_25InternalMetadataWithArenaEE27mutable_unknown_fields_slowEv[_ZN6google8protobuf8internal29InternalMetadataWithArenaBaseINS0_15UnknownFieldSetENS1_25InternalMetadataWithArenaEE27mutable_unknown_fields_slowEv]+0x15c): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAligned(unsigned long)'
Button.pb.cc:(.text._ZN6google8protobuf8internal29InternalMetadataWithArenaBaseINS0_15UnknownFieldSetENS1_25InternalMetadataWithArenaEE27mutable_unknown_fields_slowEv[_ZN6google8protobuf8internal29InternalMetadataWithArenaBaseINS0_15UnknownFieldSetENS1_25InternalMetadataWithArenaEE27mutable_unknown_fields_slowEv]+0x176): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAlignedAndAddCleanup(unsigned long, void (*)(void*))'
/tmp/ccMdby3z.o:(.rodata._ZTVN13robotjoystick6ButtonE[_ZTVN13robotjoystick6ButtonE]+0xb8): undefined reference to `google::protobuf::Message::SpaceUsedLong() const'
collect2: error: ld returned 1 exit status
当我用另一个损坏的场景编译代码时，
const string thename = "blah";
robotjoystick::Button * thebutton;
thebutton = new Button();
thebutton->set_name("john");
thebutton->set_id(12);
我得到的是这个错误：
Compiling dumbprotos.cpp
/tmp/ccaCT7Iy.o: In function `google::protobuf::internal::GetEmptyStringAlreadyInited[abi:cxx11]()':
dumbprotos.cpp:(.text._ZN6google8protobuf8internal27GetEmptyStringAlreadyInitedB5cxx11Ev[_ZN6google8protobuf8internal27GetEmptyStringAlreadyInitedB5cxx11Ev]+0x5): undefined reference to `google::protobuf::internal::fixed_address_empty_string[abi:cxx11]'
/tmp/ccfmvBXP.o: In function `AddDescriptors_Button_2eproto()':
Button.pb.cc:(.text+0xa6): undefined reference to `google::protobuf::internal::AddDescriptors(google::protobuf::internal::DescriptorTable*, void (* const*)(), int)'
/tmp/ccfmvBXP.o: In function `robotjoystick::Button::MergePartialFromCodedStream(google::protobuf::io::CodedInputStream*)':
Button.pb.cc:(.text+0x660): undefined reference to `google::protobuf::io::CodedInputStream::ReadTagFallback(unsigned int)'
Button.pb.cc:(.text+0x73f): undefined reference to `google::protobuf::internal::WireFormatLite::VerifyUtf8String(char const*, int, google::protobuf::internal::WireFormatLite::Operation, char const*)'
/tmp/ccfmvBXP.o: In function `robotjoystick::Button::SerializeWithCachedSizes(google::protobuf::io::CodedOutputStream*) const':
Button.pb.cc:(.text+0x904): undefined reference to `google::protobuf::internal::WireFormatLite::VerifyUtf8String(char const*, int, google::protobuf::internal::WireFormatLite::Operation, char const*)'
/tmp/ccfmvBXP.o: In function `robotjoystick::Button::InternalSerializeWithCachedSizesToArray(unsigned char*) const':
Button.pb.cc:(.text+0xa98): undefined reference to `google::protobuf::internal::WireFormatLite::VerifyUtf8String(char const*, int, google::protobuf::internal::WireFormatLite::Operation, char const*)'
/tmp/ccfmvBXP.o: In function `robotjoystick::Button::GetMetadata() const':
Button.pb.cc:(.text+0x1386): undefined reference to `google::protobuf::internal::AssignDescriptors(google::protobuf::internal::AssignDescriptorsTable*)'
/tmp/ccfmvBXP.o: In function `robotjoystick::Button* google::protobuf::Arena::CreateMaybeMessage<robotjoystick::Button>(google::protobuf::Arena*)':
Button.pb.cc:(.text+0x142e): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAligned(unsigned long)'
Button.pb.cc:(.text+0x144b): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAlignedAndAddCleanup(unsigned long, void (*)(void*))'
/tmp/ccfmvBXP.o: In function `google::protobuf::io::CodedInputStream::ReadVarint32(unsigned int*)':
Button.pb.cc:(.text._ZN6google8protobuf2io16CodedInputStream12ReadVarint32EPj[_ZN6google8protobuf2io16CodedInputStream12ReadVarint32EPj]+0x78): undefined reference to `google::protobuf::io::CodedInputStream::ReadVarint32Fallback(unsigned int)'
/tmp/ccfmvBXP.o: In function `google::protobuf::Arena::AllocHook(std::type_info const*, unsigned long) const':
Button.pb.cc:(.text._ZNK6google8protobuf5Arena9AllocHookEPKSt9type_infom[_ZNK6google8protobuf5Arena9AllocHookEPKSt9type_infom]+0x3d): undefined reference to `google::protobuf::Arena::OnArenaAllocation(std::type_info const*, unsigned long) const'
/tmp/ccfmvBXP.o: In function `google::protobuf::internal::ArenaStringPtr::CreateInstance(google::protobuf::Arena*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const*)':
Button.pb.cc:(.text._ZN6google8protobuf8internal14ArenaStringPtr14CreateInstanceEPNS0_5ArenaEPKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE[_ZN6google8protobuf8internal14ArenaStringPtr14CreateInstanceEPNS0_5ArenaEPKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE]+0x23e): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAligned(unsigned long)'
Button.pb.cc:(.text._ZN6google8protobuf8internal14ArenaStringPtr14CreateInstanceEPNS0_5ArenaEPKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE[_ZN6google8protobuf8internal14ArenaStringPtr14CreateInstanceEPNS0_5ArenaEPKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE]+0x25b): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAlignedAndAddCleanup(unsigned long, void (*)(void*))'
/tmp/ccfmvBXP.o: In function `google::protobuf::internal::InitSCC(google::protobuf::internal::SCCInfoBase*)':
Button.pb.cc:(.text._ZN6google8protobuf8internal7InitSCCEPNS1_11SCCInfoBaseE[_ZN6google8protobuf8internal7InitSCCEPNS1_11SCCInfoBaseE]+0x4d): undefined reference to `google::protobuf::internal::InitSCCImpl(google::protobuf::internal::SCCInfoBase*)'
/tmp/ccfmvBXP.o: In function `google::protobuf::internal::OnShutdownDestroyMessage(void const*)':
Button.pb.cc:(.text._ZN6google8protobuf8internal24OnShutdownDestroyMessageEPKv[_ZN6google8protobuf8internal24OnShutdownDestroyMessageEPKv]+0x14): undefined reference to `google::protobuf::internal::DestroyMessage(void const*)'
Button.pb.cc:(.text._ZN6google8protobuf8internal24OnShutdownDestroyMessageEPKv[_ZN6google8protobuf8internal24OnShutdownDestroyMessageEPKv]+0x19): undefined reference to `google::protobuf::internal::OnShutdownRun(void (*)(void const*), void const*)'
/tmp/ccfmvBXP.o: In function `google::protobuf::internal::InternalMetadataWithArena::default_instance()':
Button.pb.cc:(.text._ZN6google8protobuf8internal25InternalMetadataWithArena16default_instanceEv[_ZN6google8protobuf8internal25InternalMetadataWithArena16default_instanceEv]+0x5): undefined reference to `google::protobuf::UnknownFieldSet::default_instance()'
/tmp/ccfmvBXP.o: In function `google::protobuf::internal::InternalMetadataWithArenaBase<google::protobuf::UnknownFieldSet, google::protobuf::internal::InternalMetadataWithArena>::mutable_unknown_fields_slow()':
Button.pb.cc:(.text._ZN6google8protobuf8internal29InternalMetadataWithArenaBaseINS0_15UnknownFieldSetENS1_25InternalMetadataWithArenaEE27mutable_unknown_fields_slowEv[_ZN6google8protobuf8internal29InternalMetadataWithArenaBaseINS0_15UnknownFieldSetENS1_25InternalMetadataWithArenaEE27mutable_unknown_fields_slowEv]+0x15c): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAligned(unsigned long)'
Button.pb.cc:(.text._ZN6google8protobuf8internal29InternalMetadataWithArenaBaseINS0_15UnknownFieldSetENS1_25InternalMetadataWithArenaEE27mutable_unknown_fields_slowEv[_ZN6google8protobuf8internal29InternalMetadataWithArenaBaseINS0_15UnknownFieldSetENS1_25InternalMetadataWithArenaEE27mutable_unknown_fields_slowEv]+0x176): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAlignedAndAddCleanup(unsigned long, void (*)(void*))'
/tmp/ccfmvBXP.o:(.rodata._ZTVN13robotjoystick6ButtonE[_ZTVN13robotjoystick6ButtonE]+0xb8): undefined reference to `google::protobuf::Message::SpaceUsedLong() const'
collect2: error: ld returned 1 exit status
这是我用来编译代码的脚本：
#!/bin/sh
echo "Compiling dumbprotos.cpp"
echo ""
g++ dumbprotos.cpp proto_classes/Button.pb.cc -o ./pleasework -std=c++11 -lSDL2 -lprotobuf
我想这就是我需要向你们展示的一切。我错过了什么吗？我需要做什么才能编译我的 *.cpp 代码？
我在 Ubuntu 16.04.
考虑到@goduk 提供的评论后，我认为我应该进一步研究链接库问题并找到我需要获取的文件。事实证明，我没有链接到任何特定位置。
我决定查看 protobuf-3.7.1/src/README.md 下的文档，进一步探索以找到 .../lib/ 目录。在 re-reading 那些文档之后，一个特定的部分引起了我的注意。
To compile a package that uses Protocol Buffers, you need to pass
various flags to your compiler and linker. As of version 2.2.0,
Protocol Buffers integrates with pkg-config to manage this. If you
have pkg-config installed, then you can invoke it to get a list of
flags like so:
pkg-config --cflags protobuf # print compiler flags
pkg-config --libs protobuf # print linker flags
pkg-config --cflags --libs protobuf # print both
For example:
c++ my_program.cc my_proto.pb.cc `pkg-config --cflags --libs protobuf`
在我的笔记本电脑上，命令 pkg-config --cflags --libs protobuf returns -pthread -I/usr/local/include -L/usr/local/lib -lprotobuf -pthread。
我没有尝试确定正确的编译标志，而是只需要在最后使用 pkg-config --cflags --libs protobuf 调用所需的标志。
我以前从未听说过 pkg-config，但这解决了我所有的问题。
最后的 bash 脚本行现在是这样的：
g++ dumbprotos.cpp proto_classes/Button.pb.cc -o ./pleasework -std=c++11 -lSDL2 `pkg-config --cflags --libs protobuf`
感谢您的帮助。
（这 是 链接器类型问题。）
我还应该提一下，如果 protobuf 对象包含其他 protobuf 对象，您必须在命令行调用中包含这些对象：
g++ my_program.cc my_proto_imported.pb.cc my_proto_containing.pb.cc `pkg-config --cflags --libs protobuf`
表示my_proto_imported.pb.cc是在my_proto_contained.pb.cc中导入并使用的protobuf。
我最近一直在与 Google protobufs 作斗争。我写了一个名为 Button.proto.
内容如下：
syntax = "proto3";
package robotjoystick;
message Button {
string name = 1;
int32 id = 2;
uint32 state = 3;
}
我用这个命令成功编译了它（用实际计算机用户替换了 $USER）：
protoc -I=/home/$USER/robotjoystickserver --cpp_out=/home/$USER/robotjoystickserver/proto_classes Button.proto
我使用的是 protobuf 版本 3.7.1。
我的 *.cpp 文件名为 dumbprrotos.cpp 并且由于某种原因没有编译。
这是我的 *.cpp 文件：
// Client side C/C++ program to demonstrate Socket programming
#include <stdio.h>
#include <sys/socket.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <string.h>
// This line was forgotten apparently -
#include <arpa/inet.h>
// This one was also forgotten - https://www.reddit.com/r/learnprogramming/comments/3tlii5/clinux_why_is_write_or_close_not_declared_in_this/
#include <unistd.h>
// This is SDL 2.0, the joystick control library
#include <SDL2/SDL.h>
// For Ctrl+C quitting
#include <signal.h>
// for std::end
//#include <iostream>
// Now we import the header files the protobuf compiler generated.
#include "proto_classes/Button.pb.h"
// This is a standard port
#define PORT 8080
//#include<iostream>
using namespace std;
// For the protobuf generated class.
using namespace robotjoystick;
int main(int argc, char const *argv[])
{
// https://developers.google.com/protocol-buffers/docs/cpptutorial
// Verify that the version of the library that we linked against is
// compatible with the version of the headers we compiled against.
GOOGLE_PROTOBUF_VERIFY_VERSION;
// Broken method 1
/*
const string thename = "blah";
robotjoystick::Button * thebutton;
thebutton = new Button();
thebutton->set_name("john");
thebutton->set_id(12);
*/
// Broken method 2
const string thename = "blah";
robotjoystick::Button thebutton;
thebutton.set_name("john");
thebutton.set_id(12);
return 0;
}
我标记的 2 段代码是我试图完成的同一件事的 2 个版本，但都抛出相同类型的错误，我不知道如何解释它。我需要做什么才能编译此代码？
我还应该提到我在我的主目录下安装了 protobuf 3.7.1（这意味着 protobuf 的 zip 文件是在那里提取然后安装在那里）。
当前 运行 代码时出现的错误，确切地说，我收到此错误：
Compiling dumbprotos.cpp
/tmp/cc7HHVQf.o: In function `google::protobuf::internal::GetEmptyStringAlreadyInited[abi:cxx11]()':
dumbprotos.cpp:(.text._ZN6google8protobuf8internal27GetEmptyStringAlreadyInitedB5cxx11Ev[_ZN6google8protobuf8internal27GetEmptyStringAlreadyInitedB5cxx11Ev]+0x5): undefined reference to `google::protobuf::internal::fixed_address_empty_string[abi:cxx11]'
/tmp/ccMdby3z.o: In function `AddDescriptors_Button_2eproto()':
Button.pb.cc:(.text+0xa6): undefined reference to `google::protobuf::internal::AddDescriptors(google::protobuf::internal::DescriptorTable*, void (* const*)(), int)'
/tmp/ccMdby3z.o: In function `robotjoystick::Button::MergePartialFromCodedStream(google::protobuf::io::CodedInputStream*)':
Button.pb.cc:(.text+0x660): undefined reference to `google::protobuf::io::CodedInputStream::ReadTagFallback(unsigned int)'
Button.pb.cc:(.text+0x73f): undefined reference to `google::protobuf::internal::WireFormatLite::VerifyUtf8String(char const*, int, google::protobuf::internal::WireFormatLite::Operation, char const*)'
/tmp/ccMdby3z.o: In function `robotjoystick::Button::SerializeWithCachedSizes(google::protobuf::io::CodedOutputStream*) const':
Button.pb.cc:(.text+0x904): undefined reference to `google::protobuf::internal::WireFormatLite::VerifyUtf8String(char const*, int, google::protobuf::internal::WireFormatLite::Operation, char const*)'
/tmp/ccMdby3z.o: In function `robotjoystick::Button::InternalSerializeWithCachedSizesToArray(unsigned char*) const':
Button.pb.cc:(.text+0xa98): undefined reference to `google::protobuf::internal::WireFormatLite::VerifyUtf8String(char const*, int, google::protobuf::internal::WireFormatLite::Operation, char const*)'
/tmp/ccMdby3z.o: In function `robotjoystick::Button::GetMetadata() const':
Button.pb.cc:(.text+0x1386): undefined reference to `google::protobuf::internal::AssignDescriptors(google::protobuf::internal::AssignDescriptorsTable*)'
/tmp/ccMdby3z.o: In function `robotjoystick::Button* google::protobuf::Arena::CreateMaybeMessage<robotjoystick::Button>(google::protobuf::Arena*)':
Button.pb.cc:(.text+0x142e): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAligned(unsigned long)'
Button.pb.cc:(.text+0x144b): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAlignedAndAddCleanup(unsigned long, void (*)(void*))'
/tmp/ccMdby3z.o: In function `google::protobuf::io::CodedInputStream::ReadVarint32(unsigned int*)':
Button.pb.cc:(.text._ZN6google8protobuf2io16CodedInputStream12ReadVarint32EPj[_ZN6google8protobuf2io16CodedInputStream12ReadVarint32EPj]+0x78): undefined reference to `google::protobuf::io::CodedInputStream::ReadVarint32Fallback(unsigned int)'
/tmp/ccMdby3z.o: In function `google::protobuf::Arena::AllocHook(std::type_info const*, unsigned long) const':
Button.pb.cc:(.text._ZNK6google8protobuf5Arena9AllocHookEPKSt9type_infom[_ZNK6google8protobuf5Arena9AllocHookEPKSt9type_infom]+0x3d): undefined reference to `google::protobuf::Arena::OnArenaAllocation(std::type_info const*, unsigned long) const'
/tmp/ccMdby3z.o: In function `google::protobuf::internal::ArenaStringPtr::CreateInstance(google::protobuf::Arena*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const*)':
Button.pb.cc:(.text._ZN6google8protobuf8internal14ArenaStringPtr14CreateInstanceEPNS0_5ArenaEPKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE[_ZN6google8protobuf8internal14ArenaStringPtr14CreateInstanceEPNS0_5ArenaEPKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE]+0x23e): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAligned(unsigned long)'
Button.pb.cc:(.text._ZN6google8protobuf8internal14ArenaStringPtr14CreateInstanceEPNS0_5ArenaEPKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE[_ZN6google8protobuf8internal14ArenaStringPtr14CreateInstanceEPNS0_5ArenaEPKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE]+0x25b): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAlignedAndAddCleanup(unsigned long, void (*)(void*))'
/tmp/ccMdby3z.o: In function `google::protobuf::internal::InitSCC(google::protobuf::internal::SCCInfoBase*)':
Button.pb.cc:(.text._ZN6google8protobuf8internal7InitSCCEPNS1_11SCCInfoBaseE[_ZN6google8protobuf8internal7InitSCCEPNS1_11SCCInfoBaseE]+0x4d): undefined reference to `google::protobuf::internal::InitSCCImpl(google::protobuf::internal::SCCInfoBase*)'
/tmp/ccMdby3z.o: In function `google::protobuf::internal::OnShutdownDestroyMessage(void const*)':
Button.pb.cc:(.text._ZN6google8protobuf8internal24OnShutdownDestroyMessageEPKv[_ZN6google8protobuf8internal24OnShutdownDestroyMessageEPKv]+0x14): undefined reference to `google::protobuf::internal::DestroyMessage(void const*)'
Button.pb.cc:(.text._ZN6google8protobuf8internal24OnShutdownDestroyMessageEPKv[_ZN6google8protobuf8internal24OnShutdownDestroyMessageEPKv]+0x19): undefined reference to `google::protobuf::internal::OnShutdownRun(void (*)(void const*), void const*)'
/tmp/ccMdby3z.o: In function `google::protobuf::internal::InternalMetadataWithArena::default_instance()':
Button.pb.cc:(.text._ZN6google8protobuf8internal25InternalMetadataWithArena16default_instanceEv[_ZN6google8protobuf8internal25InternalMetadataWithArena16default_instanceEv]+0x5): undefined reference to `google::protobuf::UnknownFieldSet::default_instance()'
/tmp/ccMdby3z.o: In function `google::protobuf::internal::InternalMetadataWithArenaBase<google::protobuf::UnknownFieldSet, google::protobuf::internal::InternalMetadataWithArena>::mutable_unknown_fields_slow()':
Button.pb.cc:(.text._ZN6google8protobuf8internal29InternalMetadataWithArenaBaseINS0_15UnknownFieldSetENS1_25InternalMetadataWithArenaEE27mutable_unknown_fields_slowEv[_ZN6google8protobuf8internal29InternalMetadataWithArenaBaseINS0_15UnknownFieldSetENS1_25InternalMetadataWithArenaEE27mutable_unknown_fields_slowEv]+0x15c): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAligned(unsigned long)'
Button.pb.cc:(.text._ZN6google8protobuf8internal29InternalMetadataWithArenaBaseINS0_15UnknownFieldSetENS1_25InternalMetadataWithArenaEE27mutable_unknown_fields_slowEv[_ZN6google8protobuf8internal29InternalMetadataWithArenaBaseINS0_15UnknownFieldSetENS1_25InternalMetadataWithArenaEE27mutable_unknown_fields_slowEv]+0x176): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAlignedAndAddCleanup(unsigned long, void (*)(void*))'
/tmp/ccMdby3z.o:(.rodata._ZTVN13robotjoystick6ButtonE[_ZTVN13robotjoystick6ButtonE]+0xb8): undefined reference to `google::protobuf::Message::SpaceUsedLong() const'
collect2: error: ld returned 1 exit status
当我用另一个损坏的场景编译代码时，
const string thename = "blah";
robotjoystick::Button * thebutton;
thebutton = new Button();
thebutton->set_name("john");
thebutton->set_id(12);
我得到的是这个错误：
Compiling dumbprotos.cpp
/tmp/ccaCT7Iy.o: In function `google::protobuf::internal::GetEmptyStringAlreadyInited[abi:cxx11]()':
dumbprotos.cpp:(.text._ZN6google8protobuf8internal27GetEmptyStringAlreadyInitedB5cxx11Ev[_ZN6google8protobuf8internal27GetEmptyStringAlreadyInitedB5cxx11Ev]+0x5): undefined reference to `google::protobuf::internal::fixed_address_empty_string[abi:cxx11]'
/tmp/ccfmvBXP.o: In function `AddDescriptors_Button_2eproto()':
Button.pb.cc:(.text+0xa6): undefined reference to `google::protobuf::internal::AddDescriptors(google::protobuf::internal::DescriptorTable*, void (* const*)(), int)'
/tmp/ccfmvBXP.o: In function `robotjoystick::Button::MergePartialFromCodedStream(google::protobuf::io::CodedInputStream*)':
Button.pb.cc:(.text+0x660): undefined reference to `google::protobuf::io::CodedInputStream::ReadTagFallback(unsigned int)'
Button.pb.cc:(.text+0x73f): undefined reference to `google::protobuf::internal::WireFormatLite::VerifyUtf8String(char const*, int, google::protobuf::internal::WireFormatLite::Operation, char const*)'
/tmp/ccfmvBXP.o: In function `robotjoystick::Button::SerializeWithCachedSizes(google::protobuf::io::CodedOutputStream*) const':
Button.pb.cc:(.text+0x904): undefined reference to `google::protobuf::internal::WireFormatLite::VerifyUtf8String(char const*, int, google::protobuf::internal::WireFormatLite::Operation, char const*)'
/tmp/ccfmvBXP.o: In function `robotjoystick::Button::InternalSerializeWithCachedSizesToArray(unsigned char*) const':
Button.pb.cc:(.text+0xa98): undefined reference to `google::protobuf::internal::WireFormatLite::VerifyUtf8String(char const*, int, google::protobuf::internal::WireFormatLite::Operation, char const*)'
/tmp/ccfmvBXP.o: In function `robotjoystick::Button::GetMetadata() const':
Button.pb.cc:(.text+0x1386): undefined reference to `google::protobuf::internal::AssignDescriptors(google::protobuf::internal::AssignDescriptorsTable*)'
/tmp/ccfmvBXP.o: In function `robotjoystick::Button* google::protobuf::Arena::CreateMaybeMessage<robotjoystick::Button>(google::protobuf::Arena*)':
Button.pb.cc:(.text+0x142e): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAligned(unsigned long)'
Button.pb.cc:(.text+0x144b): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAlignedAndAddCleanup(unsigned long, void (*)(void*))'
/tmp/ccfmvBXP.o: In function `google::protobuf::io::CodedInputStream::ReadVarint32(unsigned int*)':
Button.pb.cc:(.text._ZN6google8protobuf2io16CodedInputStream12ReadVarint32EPj[_ZN6google8protobuf2io16CodedInputStream12ReadVarint32EPj]+0x78): undefined reference to `google::protobuf::io::CodedInputStream::ReadVarint32Fallback(unsigned int)'
/tmp/ccfmvBXP.o: In function `google::protobuf::Arena::AllocHook(std::type_info const*, unsigned long) const':
Button.pb.cc:(.text._ZNK6google8protobuf5Arena9AllocHookEPKSt9type_infom[_ZNK6google8protobuf5Arena9AllocHookEPKSt9type_infom]+0x3d): undefined reference to `google::protobuf::Arena::OnArenaAllocation(std::type_info const*, unsigned long) const'
/tmp/ccfmvBXP.o: In function `google::protobuf::internal::ArenaStringPtr::CreateInstance(google::protobuf::Arena*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const*)':
Button.pb.cc:(.text._ZN6google8protobuf8internal14ArenaStringPtr14CreateInstanceEPNS0_5ArenaEPKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE[_ZN6google8protobuf8internal14ArenaStringPtr14CreateInstanceEPNS0_5ArenaEPKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE]+0x23e): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAligned(unsigned long)'
Button.pb.cc:(.text._ZN6google8protobuf8internal14ArenaStringPtr14CreateInstanceEPNS0_5ArenaEPKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE[_ZN6google8protobuf8internal14ArenaStringPtr14CreateInstanceEPNS0_5ArenaEPKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE]+0x25b): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAlignedAndAddCleanup(unsigned long, void (*)(void*))'
/tmp/ccfmvBXP.o: In function `google::protobuf::internal::InitSCC(google::protobuf::internal::SCCInfoBase*)':
Button.pb.cc:(.text._ZN6google8protobuf8internal7InitSCCEPNS1_11SCCInfoBaseE[_ZN6google8protobuf8internal7InitSCCEPNS1_11SCCInfoBaseE]+0x4d): undefined reference to `google::protobuf::internal::InitSCCImpl(google::protobuf::internal::SCCInfoBase*)'
/tmp/ccfmvBXP.o: In function `google::protobuf::internal::OnShutdownDestroyMessage(void const*)':
Button.pb.cc:(.text._ZN6google8protobuf8internal24OnShutdownDestroyMessageEPKv[_ZN6google8protobuf8internal24OnShutdownDestroyMessageEPKv]+0x14): undefined reference to `google::protobuf::internal::DestroyMessage(void const*)'
Button.pb.cc:(.text._ZN6google8protobuf8internal24OnShutdownDestroyMessageEPKv[_ZN6google8protobuf8internal24OnShutdownDestroyMessageEPKv]+0x19): undefined reference to `google::protobuf::internal::OnShutdownRun(void (*)(void const*), void const*)'
/tmp/ccfmvBXP.o: In function `google::protobuf::internal::InternalMetadataWithArena::default_instance()':
Button.pb.cc:(.text._ZN6google8protobuf8internal25InternalMetadataWithArena16default_instanceEv[_ZN6google8protobuf8internal25InternalMetadataWithArena16default_instanceEv]+0x5): undefined reference to `google::protobuf::UnknownFieldSet::default_instance()'
/tmp/ccfmvBXP.o: In function `google::protobuf::internal::InternalMetadataWithArenaBase<google::protobuf::UnknownFieldSet, google::protobuf::internal::InternalMetadataWithArena>::mutable_unknown_fields_slow()':
Button.pb.cc:(.text._ZN6google8protobuf8internal29InternalMetadataWithArenaBaseINS0_15UnknownFieldSetENS1_25InternalMetadataWithArenaEE27mutable_unknown_fields_slowEv[_ZN6google8protobuf8internal29InternalMetadataWithArenaBaseINS0_15UnknownFieldSetENS1_25InternalMetadataWithArenaEE27mutable_unknown_fields_slowEv]+0x15c): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAligned(unsigned long)'
Button.pb.cc:(.text._ZN6google8protobuf8internal29InternalMetadataWithArenaBaseINS0_15UnknownFieldSetENS1_25InternalMetadataWithArenaEE27mutable_unknown_fields_slowEv[_ZN6google8protobuf8internal29InternalMetadataWithArenaBaseINS0_15UnknownFieldSetENS1_25InternalMetadataWithArenaEE27mutable_unknown_fields_slowEv]+0x176): undefined reference to `google::protobuf::internal::ArenaImpl::AllocateAlignedAndAddCleanup(unsigned long, void (*)(void*))'
/tmp/ccfmvBXP.o:(.rodata._ZTVN13robotjoystick6ButtonE[_ZTVN13robotjoystick6ButtonE]+0xb8): undefined reference to `google::protobuf::Message::SpaceUsedLong() const'
collect2: error: ld returned 1 exit status
这是我用来编译代码的脚本：
#!/bin/sh
echo "Compiling dumbprotos.cpp"
echo ""
g++ dumbprotos.cpp proto_classes/Button.pb.cc -o ./pleasework -std=c++11 -lSDL2 -lprotobuf
我想这就是我需要向你们展示的一切。我错过了什么吗？我需要做什么才能编译我的 *.cpp 代码？
我在 Ubuntu 16.04.
考虑到@goduk 提供的评论后，我认为我应该进一步研究链接库问题并找到我需要获取的文件。事实证明，我没有链接到任何特定位置。
我决定查看 protobuf-3.7.1/src/README.md 下的文档，进一步探索以找到 .../lib/ 目录。在 re-reading 那些文档之后，一个特定的部分引起了我的注意。
To compile a package that uses Protocol Buffers, you need to pass
various flags to your compiler and linker. As of version 2.2.0,
Protocol Buffers integrates with pkg-config to manage this. If you
have pkg-config installed, then you can invoke it to get a list of
flags like so:
pkg-config --cflags protobuf # print compiler flags
pkg-config --libs protobuf # print linker flags
pkg-config --cflags --libs protobuf # print both
For example:
c++ my_program.cc my_proto.pb.cc `pkg-config --cflags --libs protobuf`
在我的笔记本电脑上，命令 pkg-config --cflags --libs protobuf returns -pthread -I/usr/local/include -L/usr/local/lib -lprotobuf -pthread。
我没有尝试确定正确的编译标志，而是只需要在最后使用 pkg-config --cflags --libs protobuf 调用所需的标志。
我以前从未听说过 pkg-config，但这解决了我所有的问题。
最后的 bash 脚本行现在是这样的：
g++ dumbprotos.cpp proto_classes/Button.pb.cc -o ./pleasework -std=c++11 -lSDL2 `pkg-config --cflags --libs protobuf`
感谢您的帮助。 （这 是 链接器类型问题。）
我还应该提一下，如果 protobuf 对象包含其他 protobuf 对象，您必须在命令行调用中包含这些对象：
g++ my_program.cc my_proto_imported.pb.cc my_proto_containing.pb.cc `pkg-config --cflags --libs protobuf`
表示my_proto_imported.pb.cc是在my_proto_contained.pb.cc中导入并使用的protobuf。