C++ 如何在c++；？

我正在使用facebook的proxygen库构建一个简单的客户端示例。在一个目录中，我有两个对象文件如何链接它们： 我正在使用：

g++ -std=c++11 -o my_echo CurlClientMain.o  CurlClient.o -lproxygenhttpserver -lfolly -lglog -lgflags -pthread

我想我在上面的例子中遗漏了一些链接器标志，比如-lgflags。在包含some-someflag之后，可能会有助于编译。我如何知道所有可能的库标志都是什么样的，就像他们使用的一样-lproxyhttpserver

简而言之，所有这些LIB的定义或位置都在哪里。我正在使用ubuntu

以下是我的错误消息

 In function `main':
/home/kshitij/proxygen/httpclient/samples/curl/CurlClientMain.cpp:91: undefined reference to `proxygen::HTTPConnector::HTTPConnector(proxygen::HTTPConnector::Callback*, folly::HHWheelTimer*)'
/home/kshitij/proxygen/httpclient/samples/curl/CurlClientMain.cpp:102: undefined reference to `proxygen::HTTPConnector::connect(folly::EventBase*, folly::SocketAddress const&, std::chrono::duration<long, std::ratio<1l, 1000l> >, std::map<folly::AsyncSocket::OptionKey, int, std::less<folly::AsyncSocket::OptionKey>, std::allocator<std::pair<folly::AsyncSocket::OptionKey const, int> > > const&, folly::SocketAddress const&)'
/home/kshitij/proxygen/httpclient/samples/curl/CurlClientMain.cpp:91: undefined reference to `proxygen::HTTPConnector::~HTTPConnector()'
/home/kshitij/proxygen/httpclient/samples/curl/CurlClientMain.cpp:99: undefined reference to `proxygen::HTTPConnector::connectSSL(folly::EventBase*, folly::SocketAddress const&, std::shared_ptr<folly::SSLContext> const&, ssl_session_st*, std::chrono::duration<long, std::ratio<1l, 1000l> >, std::map<folly::AsyncSocket::OptionKey, int, std::less<folly::AsyncSocket::OptionKey>, std::allocator<std::pair<folly::AsyncSocket::OptionKey const, int> > > const&, folly::SocketAddress const&, std::string const&)'
/home/kshitij/proxygen/httpclient/samples/curl/CurlClientMain.cpp:91: undefined reference to `proxygen::HTTPConnector::~HTTPConnector()'
CurlClient.o: In function `CurlService::CurlClient::connectSuccess(proxygen::HTTPUpstreamSession*)':
/home/kshitij/proxygen/httpclient/samples/curl/CurlClient.cpp:69: undefined reference to `proxygen::HTTPUpstreamSession::newTransaction(proxygen::HTTPTransactionHandler*)'
collect2: error: ld returned 1 exit status
kshitij@forgetit:~/proxygen/httpclient/samples/curl$ g++ -std=c++11 -o my_echo CurlClientMain.o  CurlClient.o -lproxygenhttpserver -lfolly -lglog -lgflags -pthread
CurlClientMain.o: In function `main':
/home/kshitij/proxygen/httpclient/samples/curl/CurlClientMain.cpp:91: undefined reference to `proxygen::HTTPConnector::HTTPConnector(proxygen::HTTPConnector::Callback*, folly::HHWheelTimer*)'
/home/kshitij/proxygen/httpclient/samples/curl/CurlClientMain.cpp:102: undefined reference to `proxygen::HTTPConnector::connect(folly::EventBase*, folly::SocketAddress const&, std::chrono::duration<long, std::ratio<1l, 1000l> >, std::map<folly::AsyncSocket::OptionKey, int, std::less<folly::AsyncSocket::OptionKey>, std::allocator<std::pair<folly::AsyncSocket::OptionKey const, int> > > const&, folly::SocketAddress const&)'
/home/kshitij/proxygen/httpclient/samples/curl/CurlClientMain.cpp:91: undefined reference to `proxygen::HTTPConnector::~HTTPConnector()'
/home/kshitij/proxygen/httpclient/samples/curl/CurlClientMain.cpp:99: undefined reference to `proxygen::HTTPConnector::connectSSL(folly::EventBase*, folly::SocketAddress const&, std::shared_ptr<folly::SSLContext> const&, ssl_session_st*, std::chrono::duration<long, std::ratio<1l, 1000l> >, std::map<folly::AsyncSocket::OptionKey, int, std::less<folly::AsyncSocket::OptionKey>, std::allocator<std::pair<folly::AsyncSocket::OptionKey const, int> > > const&, folly::SocketAddress const&, std::string const&)'
/home/kshitij/proxygen/httpclient/samples/curl/CurlClientMain.cpp:91: undefined reference to `proxygen::HTTPConnector::~HTTPConnector()'
CurlClient.o: In function `CurlService::CurlClient::connectSuccess(proxygen::HTTPUpstreamSession*)':
/home/kshitij/proxygen/httpclient/samples/curl/CurlClient.cpp:69: undefined reference to `proxygen::HTTPUpstreamSession::newTransaction(proxygen::HTTPTransactionHandler*)'
collect2: error: ld returned 1 exit status

函数“main”中的

：
/home/kshitij/proxygen/httpclient/samples/curl/CurlClientMain.cpp:91:对“proxygen:：HTTPConnector:：HTTPConnector”（proxygen:：HTTPConnector:：Callback*，folly:：hwheeltimer*）的未定义引用
/home/kshitij/proxygen/httpclient/samples/curl/CurlClientMain.cpp:102:对“proxygen:：HTTPConnector:：connect（folly:：EventBase*，folly:：SocketAddress const&，std:：chrono:：duration，std:：map const&，folly:：SocketAddress const&）”的未定义引用
/home/kshitij/proxygen/httpclient/samples/curl/CurlClientMain.cpp:91:未定义对“proxygen:：HTTPConnector:：~HTTPConnector（）”的引用
/home/kshitij/proxygen/httpclient/samples/curl/CurlClientMain.cpp:99：对“proxygen:：HTTPConnector:：connectSSL（folly:：EventBase*，folly:：SocketAddress const&，std:：shared_ptr const&，ssl_session_st*，std:：chrono:：duration，std:：map const&，folly:：SocketAddress const&，std:：string const&）”的未定义引用
/home/kshitij/proxygen/httpclient/samples/curl/CurlClientMain.cpp:91:未定义对“proxygen:：HTTPConnector:：~HTTPConnector（）”的引用
CurlClient.o:在函数“CurlService:：CurlClient:：connectSuccess（proxygen:：HTTPUpstreamSession*）”中：
/home/kshitij/proxygen/httpclient/samples/curl/CurlClient.cpp:69:对“proxygen:：HTTPUpstreamSession:：newTransaction（proxygen:：HTTPTransactionHandler*）”的未定义引用
collect2:错误：ld返回了1个退出状态
kshitij@forgetit：~/proxygen/httpclient/samples/curl$g++-std=c++11-o my_echo CurlClientMain.o CurlClient.o-lproxygenhttpserver-lfolly-lglog-lgflags-pthread
o:在函数'main'中：
/home/kshitij/proxygen/httpclient/samples/curl/CurlClientMain.cpp:91:对“proxygen:：HTTPConnector:：HTTPConnector”（proxygen:：HTTPConnector:：Callback*，folly:：hwheeltimer*）的未定义引用
/home/kshitij/proxygen/httpclient/samples/curl/CurlClientMain.cpp:102:对“proxygen:：HTTPConnector:：connect（folly:：EventBase*，folly:：SocketAddress const&，std:：chrono:：duration，std:：map const&，folly:：SocketAddress const&）”的未定义引用
/home/kshitij/proxygen/httpclient/samples/curl/CurlClientMain.cpp:91:未定义对“proxygen:：HTTPConnector:：~HTTPConnector（）”的引用
/home/kshitij/proxygen/httpclient/samples/curl/CurlClientMain.cpp:99：对“proxygen:：HTTPConnector:：connectSSL（folly:：EventBase*，folly:：SocketAddress const&，std:：shared_ptr const&，ssl_session_st*，std:：chrono:：duration，std:：map const&，folly:：SocketAddress const&，std:：string const&）”的未定义引用
/home/kshitij/proxygen/httpclient/samples/curl/CurlClientMain.cpp:91:未定义对“proxygen:：HTTPConnector:：~HTTPConnector（）”的引用
CurlClient.o:在函数“CurlService:：CurlClient:：connectSuccess（proxygen:：HTTPUpstreamSession*）”中：
/home/kshitij/proxygen/httpclient/samples/curl/CurlClient.cpp:69:对“proxygen:：HTTPUpstreamSession:：newTransaction（proxygen:：HTTPTransactionHandler*）”的未定义引用
collect2:错误：ld返回了1个退出状态

我如何知道所有可能的库标志都是什么样的，就像他们使用的一样-lproxyhttpserver

这取决于您的编译环境

您似乎在linux中使用GNU编译器。有一个工具可以列出所有已安装的共享库：

ldconfig -p

您将得到一个这样的行列表

libpthread.so.0 (libc6,x86-64, OS ABI: Linux 2.6.32) => /lib/x86_64-linux-gnu/libpthread.so.0

删除

lib

前缀和扩展名

.so.X

，就可以得到库的名称。在本例中，它是

pthread

。要与库链接，请使用选项

-lNAME

。因此，在本例中，

-lpthread

简言之，所有这些LIB的定义或位置在哪里

---

=>

的右侧部分是库的完整路径。

您得到的确切错误消息是什么？@πάνταῥεῖ 未定义的引用错误…：我正在编辑带有错误消息的问题

-lsomething

只是查找

libsomething.a

/

.so

在配置的库路径中（默认值通常是

/lib

/usr/lib加上下面的一些其他内容，有多拱支持）；您可以在这些目录中找到已安装的库。@MatteoItalia我查看了它，但为什么会出现这些未定义的引用错误。我知道错误是由链接器引起的。我有两个对象文件，我用来链接和构建的命令已经提到了。什么会导致错误？只是吹毛求疵，但在这种情况下，

lib

实际上是一个前缀：）