我目前正在尝试在VSCode中开发一个C++跨平台项目，其中应该包括我使用vcpkg下载的Poco库。然后我遵循了这个教程：https://www.codeproject.com/Articles/252566/Learning-Poco-GET-with-HTTP但我不能解决文章中显示的未定义引用错误。下面是我的main（httpGet.cpp）（我从上面的链接复制）：
#include <Poco/Net/HTTPClientSession.h>
#include <Poco/Net/HTTPRequest.h>
#include <Poco/Net/HTTPResponse.h>
#include <Poco/StreamCopier.h>
#include <Poco/Path.h>
#include <Poco/URI.h>
#include <Poco/Exception.h>
#include <iostream>
#include <string>
using namespace Poco::Net;
using namespace Poco;
using namespace std;
int main(int argc, char **argv)
{
if (argc != 2)
{
cout << "Usage: " << argv[0] << " <uri>" << endl;
cout << " fetches the resource identified by <uri> and print it" << endl;
return -1;
}
try
{
// prepare session
URI uri(argv[1]);
HTTPClientSession session(uri.getHost(), uri.getPort());
// prepare path
string path(uri.getPathAndQuery());
if (path.empty()) path = "/";
// send request
HTTPRequest req(HTTPRequest::HTTP_GET, path, HTTPMessage::HTTP_1_1);
session.sendRequest(req);
// get response
HTTPResponse res;
cout << res.getStatus() << " " << res.getReason() << endl;
// print response
istream &is = session.receiveResponse(res);
StreamCopier::copyStream(is, cout);
}
catch (Exception &ex)
{
cerr << ex.displayText() << endl;
return -1;
}
return 0;
}下面是我的CMakeLists.txt：
cmake_minimum_required(VERSION 3.16)
set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(PocoNet_DIR "C:/vcpkg/installed/x64-windows/share/poco")
set(PocoFoundation_DIR "C:/vcpkg/installed/x64-windows/share/poco")
set(VCPKG_TARGET_TRIPLET "x64-windows"
CACHE STRING "")
set(CMAKE_TOOLCHAIN_FILE "C:/vcpkg/scripts/buildsystems/vcpkg.cmake"
CACHE STRING "")
project(TryPOCO)
find_package(Poco CONFIG REQUIRED Net)
find_package(PocoNet REQUIRED)
include_directories("C:/vcpkg/installed/x64-windows/include")
link_directories("C:/vcpkg/installed/x64-windows/lib")
add_executable(${PROJECT_NAME} httpGet.cpp)
target_link_libraries(${PROJECT_NAME} PRIVATE PocoNet)下面是我得到的错误：
[build] CMakeFiles\TryPOCO.dir/objects.a(httpGet.cpp.obj): In function `main':
[build] C:/TesiMag/ProveVSCode/TryPOCO/httpGet.cpp:27: undefined reference to `Poco::URI::URI(char const*)'
[build] C:/TesiMag/ProveVSCode/TryPOCO/httpGet.cpp:28: undefined reference to `Poco::URI::getPort() const'
[build] C:/TesiMag/ProveVSCode/TryPOCO/httpGet.cpp:28: undefined reference to `Poco::Net::HTTPClientSession::HTTPClientSession(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, unsigned short)'
[build] C:/TesiMag/ProveVSCode/TryPOCO/httpGet.cpp:31: undefined reference to `Poco::URI::getPathAndQuery[abi:cxx11]() const'
[build] C:/TesiMag/ProveVSCode/TryPOCO/httpGet.cpp:35: undefined reference to `Poco::Net::HTTPRequest::HTTPRequest(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'
[build] C:/TesiMag/ProveVSCode/TryPOCO/httpGet.cpp:36: undefined reference to `Poco::Net::HTTPClientSession::sendRequest(Poco::Net::HTTPRequest&)'
[build] C:/TesiMag/ProveVSCode/TryPOCO/httpGet.cpp:39: undefined reference to `Poco::Net::HTTPResponse::HTTPResponse()'
[build] C:/TesiMag/ProveVSCode/TryPOCO/httpGet.cpp:43: undefined reference to `Poco::Net::HTTPClientSession::receiveResponse(Poco::Net::HTTPResponse&)'
[build] C:/TesiMag/ProveVSCode/TryPOCO/httpGet.cpp:44: undefined reference to `Poco::StreamCopier::copyStream(std::istream&, std::ostream&, unsigned long long)'
[build] C:/TesiMag/ProveVSCode/TryPOCO/httpGet.cpp:39: undefined reference to `Poco::Net::HTTPResponse::~HTTPResponse()'
[build] C:/TesiMag/ProveVSCode/TryPOCO/httpGet.cpp:35: undefined reference to `Poco::Net::HTTPRequest::~HTTPRequest()'
[build] C:/TesiMag/ProveVSCode/TryPOCO/httpGet.cpp:28: undefined reference to `Poco::Net::HTTPClientSession::~HTTPClientSession()'
[build] C:/TesiMag/ProveVSCode/TryPOCO/httpGet.cpp:27: undefined reference to `Poco::URI::~URI()'
[build] C:/TesiMag/ProveVSCode/TryPOCO/httpGet.cpp:39: undefined reference to `Poco::Net::HTTPResponse::~HTTPResponse()'
[build] C:/TesiMag/ProveVSCode/TryPOCO/httpGet.cpp:35: undefined reference to `Poco::Net::HTTPRequest::~HTTPRequest()'
[build] C:/TesiMag/ProveVSCode/TryPOCO/httpGet.cpp:28: undefined reference to `Poco::Net::HTTPClientSession::~HTTPClientSession()'
[build] C:/TesiMag/ProveVSCode/TryPOCO/httpGet.cpp:27: undefined reference to `Poco::URI::~URI()'
[build] C:/TesiMag/ProveVSCode/TryPOCO/httpGet.cpp:48: undefined reference to `Poco::Exception::displayText[abi:cxx11]() const'
[build] CMakeFiles\TryPOCO.dir/objects.a(httpGet.cpp.obj): In function `Poco::Net::Impl::IPv4SocketAddressImpl::host() const':
[build] C:/vcpkg/installed/x64-windows/include/Poco/Net/SocketAddressImpl.h:81: undefined reference to `Poco::Net::IPAddress::IPAddress(void const*, int)'
[build] CMakeFiles\TryPOCO.dir/objects.a(httpGet.cpp.obj): In function `Poco::Net::Impl::IPv6SocketAddressImpl::host() const':
[build] C:/vcpkg/installed/x64-windows/include/Poco/Net/SocketAddressImpl.h:143: undefined reference to `Poco::Net::IPAddress::IPAddress(void const*, int, unsigned int)'
[build] CMakeFiles\TryPOCO.dir/objects.a(httpGet.cpp.obj):httpGet.cpp:(.rdata$_ZTVN4Poco3Net4Impl21IPv6SocketAddressImplE[_ZTVN4Poco3Net4Impl21IPv6SocketAddressImplE]+0x50): undefined reference to `Poco::Net::Impl::IPv6SocketAddressImpl::toString[abi:cxx11]() const'
[build] CMakeFiles\TryPOCO.dir/objects.a(httpGet.cpp.obj): In function `Poco::Net::Impl::IPv6SocketAddressImpl::~IPv6SocketAddressImpl()':
[build] C:/vcpkg/installed/x64-windows/include/Poco/Net/SocketAddressImpl.h:118: undefined reference to `Poco::Net::Impl::SocketAddressImpl::~SocketAddressImpl()'
[build] CMakeFiles\TryPOCO.dir/objects.a(httpGet.cpp.obj):httpGet.cpp:(.rdata$_ZTVN4Poco3Net4Impl21IPv4SocketAddressImplE[_ZTVN4Poco3Net4Impl21IPv4SocketAddressImplE]+0x50): undefined reference to `Poco::Net::Impl::IPv4SocketAddressImpl::toString[abi:cxx11]() const'
[build] CMakeFiles\TryPOCO.dir/objects.a(httpGet.cpp.obj): In function `Poco::Net::Impl::IPv4SocketAddressImpl::~IPv4SocketAddressImpl()':
[build] C:/vcpkg/installed/x64-windows/include/Poco/Net/SocketAddressImpl.h:56: undefined reference to `Poco::Net::Impl::SocketAddressImpl::~SocketAddressImpl()'
[build] CMakeFiles\TryPOCO.dir/objects.a(httpGet.cpp.obj):httpGet.cpp:(.rdata$.refptr._ZN4Poco3Net11HTTPRequest8HTTP_GETB5cxx11E[.refptr._ZN4Poco3Net11HTTPRequest8HTTP_GETB5cxx11E]+0x0): undefined reference to `Poco::Net::HTTPRequest::HTTP_GET[abi:cxx11]'
[build] CMakeFiles\TryPOCO.dir/objects.a(httpGet.cpp.obj):httpGet.cpp:(.rdata$.refptr._ZN4Poco3Net11HTTPMessage8HTTP_1_1B5cxx11E[.refptr._ZN4Poco3Net11HTTPMessage8HTTP_1_1B5cxx11E]+0x0): undefined reference to `Poco::Net::HTTPMessage::HTTP_1_1[abi:cxx11]'
[build] collect2.exe: error: ld returned 1 exit status
[build] mingw32-make.exe[2]: *** [CMakeFiles\TryPOCO.dir\build.make:86: TryPOCO.exe] Error 1
[build] mingw32-make.exe[1]: *** [CMakeFiles\Makefile2:75: CMakeFiles/TryPOCO.dir/all] Error 2
[build] mingw32-make.exe: *** [Makefile:83: all] Error 2
[build] Compilazione terminata con codice di uscita 2我使用的编译器是g++（x86_64-posix-seh-rev 0，Built by MinGW-W 64 project）8.1.0。
我想这是一个链接器错误，但我是CMake的新手，所以我真的不知道是否有任何其他库，我应该添加到 target_link_libraries 或其他地方在CMakeLists.txt。我也不知道CMakeLists.txt是否写得很好，因为这是我第一次使用CMake。
提前感谢您的回答。
2条答案
按热度按时间enyaitl31#
我认为你需要在CMakeLists.txt中找到一个find_library。
请访问https://cmake.org/cmake/help/cmake2.6docs.html#command:find_library
qlckcl4x2#
给予答案太晚了，不过好吧。我注意到，当尝试使用其他与
vcpkg一起安装的库时，会出现类似的错误（我在fmt中也遇到过类似的错误）。另外，当我尝试使用另一个编译器时（我将编译器从mingw更改为msvc），这个错误消失了。我希望这些观察对某人有用）