Curl causes openssl error - c++

Question

My current curl setup to call a webpage, save it into a string, and reiterate the process after sleeping for a second. This is the code to write into the string:
#include <curl/curl.h>
#include <string>
#include <iostream>
#include <thread>
#include <chrono>
size_t curl_writefunc(void* ptr, size_t size, size_t nmemb, std::string* data)
{
data->append((const char*)ptr, size * nmemb);
return size * nmemb;
}
void curl_handler(std::string& data)
{
int http_code = 0;
CURL* curl;
// Initialize cURL
curl = curl_easy_init();
// Set the function to call when there is new data
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, curl_writefunc);
// Set the parameter to append the new data to
curl_easy_setopt(curl, CURLOPT_WRITEDATA, &data);
// Set the URL to download; just for this question.
curl_easy_setopt(curl, CURLOPT_URL, "http://www.example.com/");
// Download
curl_easy_perform(curl);
// Get the HTTP response code
curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &http_code);
// Clean up
curl_easy_cleanup(curl);
curl_global_cleanup();
}
int main()
{
bool something = true;
std::string data;
while (something)
{
curl_handler(data);
std::cout << data << '\n';
data.clear();
std:: this_thread:: sleep_for (std:: chrono:: seconds(1));
}
}
However it runs into a problem about 20 minutes into runtime and this is the message it confronts me with:
140377776379824:error:02001018:system library:fopen:Too many open files:bss_file.c:173:fopen('/etc/ssl/openssl.cnf','rb')
140377776379824:error:2006D002:BIO routines:BIO_new_file:system lib:bss_file.c:178:
140377776379824:error:0E078002:configuration file routines:DEF_LOAD:system lib:conf_def.c:199:
It seems to stem from an openssl file, that does not close once it has fullfilled its task in the single iteration. If iterated more than once, the open files add up and are bound to enter into an error at some point.
I am still much of a beginner programmer, and therefore don't want to start messing with openSSL, so I came here to ask, wether there is a solution for this kind of problem. Could it be solved by declaring the curl object outside of the recalled function?

Answer 1

What has to be done is simply declaring the handle and its settings before getting the data. Only the actual download and its accompanying response is then reiterated in the loop. It is encouraged to re-use a handler as often as needed, since part of its resources (like the files opened in this session), may need to redeployed again.