I am using yahoo-finance api in my task.
I installed curl with visual studio nmake, and this is info of my curl package:
libcurl-vc22-x64-debug-dll-ssl-dll-zlib-dll-ipv6-sspi
Then I write a toy code for testing but I got the errors below.
Build started...
1>------ Build started: Project: del3, Configuration: Debug x64 ------
1>Source.obj : error LNK2019: unresolved external symbol __imp_curl_easy_init referenced in function main
1>Source.obj : error LNK2019: unresolved external symbol __imp_curl_easy_setopt referenced in function main
1>Source.obj : error LNK2019: unresolved external symbol __imp_curl_easy_cleanup referenced in function main
1>C:\Users\user\source\repos\del3\x64\Debug\del3.exe : fatal error LNK1120: 3 unresolved externals
1>Done building project "del3.vcxproj" -- FAILED.
I tried to link the libs manually like #pragma comment(lib, "ws2_32.lib") or add the lib in the properties->linker->input->additional dependencies but not it didn't work.
I also read this article https://curl.se/mail/lib-2018-07/0079.html
But I don't really undertand.
Can someone help me? Thanks!
#include <curl/curl.h>
#include <sstream>
#pragma comment(lib, "ws2_32.lib")
#pragma comment(lib, "Wldap32.lib")
#pragma comment(lib, "crypt32.lib")
#pragma comment(lib, "normaliz.lib")
size_t writeCallback(char* content, size_t size, size_t nmemb, void* userdata) {
// Append the content to user data
((std::string*)userdata)->append(content, size * nmemb);
// Return the real content size
return size * nmemb;
}
int main() {
CURL* curl = curl_easy_init();
std::string responseBuffer;
std::string url = "https://query1.finance.yahoo.com/v7/finance/download/^GSPC?period1=1512086400&period2=1514678400&interval=1d&events=history";
if (curl) {
curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
// Write result into the buffer
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, writeCallback);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, &responseBuffer);
// Perform the request
// CURLcode res = curl_easy_perform(curl);
// Cleanup
curl_easy_cleanup(curl);
}
return 0;
}
Related
#include <iostream>
#include <fstream>
#include <type_traits>
#include <Windows.h>
#include "abase.h"
using namespace std;
class Storage {
string _path;
public:
Storage(string path);
~Storage() = default;
template <typename T >
bool writeFile(string fileName,
typename enable_if<is_base_of<ABase, T>::value, T >::type* data);
}
Definition...
#include "storage.h"
Storage::Storage(string path)
{
this->_path = path;
}
template <typename T >
bool Storage::writeFile(string fileName,
typename enable_if<is_base_of<ABase, T>::value, T >::type* data){
return true;
}
Im still getting error by Linker:
LNK2019 unresolved external symbol "public: bool __thiscall
Storage::writeFile(class std::basic_string,class std::allocator >,class AFile*)"
(??$writeFile#VAFile###Storage##QAE_NV?$basic_string#DU?$char_traits#D#std##V?$allocator#D#2##std##PAVAFile###Z)
referenced in function _main
Why am i getting it if code is looking right. Its generic definition of method in a class and Im trying to constrain class type passing to the method.
And the AFile is inherited from ABase.
ABase is abstract class.
Simple usage in main:
Storage* s = new Storage("C:\\aPath...");
AFile* afile = new AFile();
s->writeFile<AFile>("a.txt", afile);
To solve your linking error you can explicitly instantiate[1] your template member function in the Storage.cpp like this:
template
bool Storage::writeFile<AFile>(string fileName,
enable_if<is_base_of<ABase, AFile>::value, AFile>::type* data);
so the compiler creates the function and the linker can find.
It's better to move the definitions in the header file - Why can templates only be implemented in the header file?.
I am trying to run my code using the library pocketsphinx. Even though I have used the .lib files for the library it still isn't working. My code:
#include "stdafx.h"
#include <pocketsphinx.h>
#define MODELDIR "c:/sphinx/model"
int main(int argc, char *argv[])
{
ps_decoder_t *ps = NULL;
cmd_ln_t *config = NULL;
config = cmd_ln_init(NULL, ps_args(), TRUE,
"-hmm", MODELDIR "/en-us/en-us",
"-lm", MODELDIR "/en-us/en-us.lm.bin",
"-dict", MODELDIR "/en-us/cmudict-en-us.dict",
NULL);
return 0;
}
Errors:
Error LNK2019 unresolved external symbol _cmd_ln_init referenced in function _main
Error LNK2019 unresolved external symbol _ps_args referenced in function _main
shows error calling vc++ 2010 express sp1 method of a object:
error LNK2019: unresolved external symbol "public: int __thiscall
oper::ShowMyResult(void)" (?ShowMyResult#oper##QAEHXZ) referenced in
function _wmain
ooad_oops_exer.h
#include "stdafx.h"
class oper {
public:
void DisplayDefault( );
void DisplayWidth( int n );
void DisplayLongs( );
int ShowMyResult();
};
ooad_oops_exer.cpp
#include "ooad_oops_exer.h"
//
#ifndef SOCKET_CLIENT_CLASS
#define SOCKET_CLIENT_CLASS
const double d1 = 1.23456789;
const long l1 = 16;
int base = 10;
void oper::DisplayDefault( )
{
cout << endl << "default display" << endl;
}
void oper::DisplayWidth( int n )
{
cout << endl << "fixed width display set to " << n << ".\n";
}
void oper::DisplayLongs( )
{
cout <<endl<<"hello";
}
int oper::ShowMyResult()
{
DisplayWidth(15);
DisplayDefault( );
cout <<endl<<"ShowMyResult";
return 0;
}
//
#endif
main.cpp
#include "stdafx.h"
#include "ooad_oops_exer.h"
int _tmain(int argc, _TCHAR* argv[])
{
oper op;
int k = op.ShowMyResult();
cin.get();
return 0;
}
EDIT
1> Generating Code... 1>Debug\ooad_oops_exer.obj : warning LNK4042:
object specified more than once; extras ignored 1>main.obj : error
LNK2019: unresolved external symbol "public: int __thiscall
oper::ShowMyResult(void)" (?ShowMyResult#oper##QAEHXZ) referenced in
function _wmain 1>C:\xxx\OOAD_OOPS_PROJ\Debug\OOAD_OOPS_PROJ.exe :
fatal error LNK1120: 1 unresolved externals 1>
The following is part of the example code from http://curl.haxx.se/libcurl/c/sendrecv.html:
static int wait_on_socket(curl_socket_t sockfd, int for_recv, long timeout_ms)
{
struct timeval tv;
fd_set infd, outfd, errfd;
int res;
tv.tv_sec = timeout_ms / 1000;
tv.tv_usec= (timeout_ms % 1000) * 1000;
FD_ZERO(&infd);
FD_ZERO(&outfd);
FD_ZERO(&errfd);
FD_SET(sockfd, &errfd); /* always check for error */
if(for_recv)
{
FD_SET(sockfd, &infd);
}
else
{
FD_SET(sockfd, &outfd);
}
///* select() returns the number of signalled sockets or -1 */
res = select(sockfd + 1, &infd, &outfd, &errfd, &tv);
return res;
}
It worked fine on Linux, but when I brought it over Visual Studio 2010, it complains about the select() function. I compiled and linked all the cURL libraries/dlls correctly, and I even downloaded stuff as http request.
But when I tried to use the socket select() function, it complains with the following error:
error LNK2028: unresolved token (0A00034C) "extern "C" int __stdcall select(int,struct fd_set *,struct fd_set *,struct fd_set *,struct timeval const *)" (?select##$$J220YGHHPAUfd_set##00PBUtimeval###Z) referenced in function "int __cdecl `anonymous namespace'::wait_on_socket(unsigned int,int,long)" (?wait_on_socket#?A0x7d9db21b##$$FYAHIHJ#Z)
error LNK2019: unresolved external symbol "extern "C" int __stdcall select(int,struct fd_set *,struct fd_set *,struct fd_set *,struct timeval const *)" (?select##$$J220YGHHPAUfd_set##00PBUtimeval###Z) referenced in function "int __cdecl `anonymous namespace'::wait_on_socket(unsigned int,int,long)" (?wait_on_socket#?A0x7d9db21b##$$FYAHIHJ#Z)
Also, it seems that the select() function is compatible with Windows:
http://msdn.microsoft.com/en-us/library/ms740141(VS.85).aspx
Am I missing something? Can someone tell me how to get around this problem?
Thanks, --Rudy
You must link with the Microsoft socket library. Tell your linker to use Ws2_32.lib within your project.
In Visual Studio 2010 add this lib to Project->Properties->Linker->Input->Add. Dependencies.
Or add this lib inside your code with:
#pragma comment(lib, "Ws2_32.lib")
I have followed this tutorial here as mentioned exactly
I now try to run simple OpenCV code on Visual Studio but it I keep getting linker errors.
I am trying this OpenCV tutorial in particular
Here is the error I keep getting :
1>Linking...
1>LINK : warning LNK4067: ambiguous entry point; selected 'mainCRTStartup'
1>OpenCV_Proj.obj : error LNK2019: unresolved external symbol "int __cdecl cv::waitKey(int)" (?waitKey#cv##YAHH#Z) referenced in function _main
1>OpenCV_Proj.obj : error LNK2019: unresolved external symbol "void __cdecl cv::imshow(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &,class cv::_InputArray const &)" (?imshow#cv##YAXABV?$basic_string#DU?$char_traits#D#std##V?$allocator#D#2##std##ABV_InputArray#1##Z) referenced in function _main
1>OpenCV_Proj.obj : error LNK2019: unresolved external symbol "public: __thiscall cv::_InputArray::_InputArray(class cv::Mat const &)" (??0_InputArray#cv##QAE#ABVMat#1##Z) referenced in function _main
1>OpenCV_Proj.obj : error LNK2019: unresolved external symbol "void __cdecl cv::namedWindow(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &,int)" (?namedWindow#cv##YAXABV?$basic_string#DU?$char_traits#D#std##V?$allocator#D#2##std##H#Z) referenced in function _main
1>OpenCV_Proj.obj : error LNK2019: unresolved external symbol "class cv::Mat __cdecl cv::imread(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &,int)" (?imread#cv##YA?AVMat#1#ABV?$basic_string#DU?$char_traits#D#std##V?$allocator#D#2##std##H#Z) referenced in function _main
1>OpenCV_Proj.obj : error LNK2019: unresolved external symbol "void __cdecl cv::fastFree(void *)" (?fastFree#cv##YAXPAX#Z) referenced in function "public: __thiscall cv::Mat::~Mat(void)" (??1Mat#cv##QAE#XZ)
1>OpenCV_Proj.obj : error LNK2019: unresolved external symbol "public: void __thiscall cv::Mat::copySize(class cv::Mat const &)" (?copySize#Mat#cv##QAEXABV12##Z) referenced in function "public: class cv::Mat & __thiscall cv::Mat::operator=(class cv::Mat const &)" (??4Mat#cv##QAEAAV01#ABV01##Z)
1>OpenCV_Proj.obj : error LNK2019: unresolved external symbol "public: void __thiscall cv::Mat::deallocate(void)" (?deallocate#Mat#cv##QAEXXZ) referenced in function "public: void __thiscall cv::Mat::release(void)" (?release#Mat#cv##QAEXXZ)
1>C:\Users\Saher\Documents\Visual Studio 2008\Projects\OpenCV_Proj\Debug\OpenCV_Proj.exe : fatal error LNK1120: 8 unresolved externals``
For the following code :
// OpenCV_Proj.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <iostream>
using namespace cv;
using namespace std;
int main( int argc, char** argv )
{
if( argc != 2)
{
cout <<" Usage: display_image ImageToLoadAndDisplay" << endl;
return -1;
}
Mat image;
image = imread(argv[1], CV_LOAD_IMAGE_COLOR); // Read the file
if(! image.data ) // Check for invalid input
{
cout << "Could not open or find the image" << std::endl ;
return -1;
}
namedWindow( "Display window", CV_WINDOW_AUTOSIZE );// Create a window for display.
imshow( "Display window", image ); // Show our image inside it.
waitKey(0); // Wait for a keystroke in the window
return 0;
}
int _tmain(int argc, _TCHAR* argv[])
{
return 0;
}
I have been trying to get OpenCV to work for VS2008 for a while and any help regarding this issue will be apprectiated.
NOTE: In the readme file of the tutorial the following is what I followed:
1) Add build\bin and one of build\{x86|x64}\{vc9\vc10\mingw}\bin to your system path (to use DLLs)
Add build\{x86|x64}\{vc9\vc10\mingw}\lib or
build\{x86|x64}\{vc9\vc10\mingw}\staticlib as library directories to your linker settings,
Add build\include and build\include\opencv as include directories to your compiler settings.
Any help with getting this to work is really appreciated.
Those symbols are defined inside the OpenCV libraries, so you need to configure the project and let the linker know which OpenCV libraries you are using.
At the very least you should add: opencv_core230.lib and opencv_highgui230.lib (for OpenCV 2.3.0)
For more info on how to do this on VS2010, check this tutorial.
Go to properties->Linker->input and
add cv210.lib; cxcore210.lib; highgui210.lib;cvaux210.lib;
Your problem will be solved.
Have a happy coding....
I faced the same issue. After using dumpbin to see the exported symbols of highgui, I found that the linker is trying to link against a symbol that has debug_build_guard at the end.
If you built OPENCV in release mode, You cannot compile your application in DEBUG mode. Try flipping it to RELEASE and it magically works :)