I am trying to test run the first example in curlpp and I am getting the error "Undefined symbol: _curl_easy_setopt". I have an idea that this is a problem with how I have tried linking the library. Below is my methodology.
header search paths -> for both debug and release -> (I typed) /usr/local/include
library search paths -> for both debug and release -> (I typed) /usr/local/lib
other linker flags -> for both debug and release -> (I typed) -lcurlpp
I ran the the example with an API url I have used in python successfully in place of "example.com".This is a picture of the full error. Thank you!`
#include <string>
#include <sstream>
#include <iostream>
#include <curlpp/cURLpp.hpp>
#include <curlpp/Easy.hpp>
#include <curlpp/Options.hpp>
namespace
{
const long MyPort = 80;
}
/**
* This example is made to show you how you can use the Options.
*/
int main(int, char **)
{
try
{
curlpp::Cleanup myCleanup;
// First easy example.
{
// The first easiest example is to retreive the content of
// a web page and put it in a stream.
std::cout << curlpp::options::Url("https://www.alphavantage.co/query?function=TIME_SERIES_INTRADAY&symbol=VSLR&frequency=5min&outputsize=full&datatype=json&apikey=IGDV8B3MO9GQ9R35");
// You don't need to use just the standard outputs. You
// can use any stream:
std::ostringstream os;
os << curlpp::options::Url("https://www.alphavantage.co/query?function=TIME_SERIES_INTRADAY&symbol=VSLR&frequency=5min&outputsize=full&datatype=json&apikey=IGDV8B3MO9GQ9R35");
}
// More elaborate example.
{
// What the previous example done there was simply
// to create a curlpp::Easy class, which is the basic
// object in cURLpp, and then set the Url option.
// curlpp::options classes are the primitives that allow to specify
// values to the requests.
curlpp::options::Url myUrl(std::string("https://www.alphavantage.co/query?function=TIME_SERIES_INTRADAY&symbol=VSLR&frequency=5min&outputsize=full&datatype=json&apikey=IGDV8B3MO9GQ9R35"));
curlpp::Easy myRequest;
myRequest.setOpt(myUrl);
// Now that all the options we wanted to set are there, we need to
// actually do the request. the "perform" method does actually that.
// With that call, the request will be done and the content of that URL
// will be printed in std::cout (which is the default).
myRequest.perform();
// If we wanted to put the content of the URL within a string stream
// (or any type of std::ostream, for that matter), like the first example,
// we would use the WriteStrem option like this:
std::ostringstream os;
curlpp::options::WriteStream ws(&os);
myRequest.setOpt(ws);
myRequest.perform();
// There is some shorcut within curlpp that allow you to write shorter code
// like this:
os << myRequest;
// That would do exactly what the previous code was doing.
}
// Creation of the URL option.
curlpp::options::Url myUrl(std::string("https://www.alphavantage.co/query?function=TIME_SERIES_INTRADAY&symbol=VSLR&frequency=5min&outputsize=full&datatype=json&apikey=IGDV8B3MO9GQ9R35"));
// Copy construct from the other URL.
curlpp::options::Url myUrl2(myUrl);
// Creation of the port option.
curlpp::options::Port myPort(MyPort);
// Creation of the request.
curlpp::Easy myRequest;
// Creation of an option that contain a copy of the URL option.
curlpp::OptionBase *mytest = myUrl.clone();
myRequest.setOpt(*mytest);
// You can reuse the base option for other type of option
// and set the option to the request. but first, don't forget
// to delete the previous memory. You can delete it since the
// option is internally duplicated for the request.
delete mytest;
mytest = myPort.clone();
myRequest.setOpt(*mytest);
delete mytest;
// You can clone an option directly to the same type of
// option.
curlpp::options::Url *myUrl3 = myUrl.clone();
myRequest.setOpt(myUrl3);
// Now myUrl3 is owned by the request we will NOT use
// it anymore.
// You don't need to declare an option if you just want
// to use it once.
myRequest.setOpt(curlpp::options::Url("https://www.alphavantage.co/query?function=TIME_SERIES_INTRADAY&symbol=VSLR&frequency=5min&outputsize=full&datatype=json&apikey=IGDV8B3MO9GQ9R35"));
// Note that the previous line wasn't really efficient
// because we create the option, this option is duplicated
// for the request and then the option destructor is called.
// You can use this instead:
myRequest.setOpt(new curlpp::options::Url("https://www.alphavantage.co/query?function=TIME_SERIES_INTRADAY&symbol=VSLR&frequency=5min&outputsize=full&datatype=json&apikey=IGDV8B3MO9GQ9R35"));
// Note that with this the request will use directly this
// instance we just created. Be aware that if you pass an
// Option pointer to the setOpt function, it will consider
// the instance has its own instance. The Option instance
// will be deleted when the request will be deleted, so
// don't use the instance further in your code.
// Doing the previous line is efficient as this:
myRequest.setOpt(myUrl.clone());
// You can retreive the value of a specific option.
std::cout << myUrl2.getValue() << std::endl;
// Perform the transaction with the options set.
myRequest.perform();
}
catch( curlpp::RuntimeError &e )
{
std::cout << e.what() << std::endl;
}
catch( curlpp::LogicError &e )
{
std::cout << e.what() << std::endl;
}
return 0;
}
The missing symbol _curl_easy_setopt and the curlpp homepage tells me that curlpp is a C++ wrapper around the C library libcurl.
You therefore need to add -lcurl to link with that library too when compiling.