Manpages - curl_easy_perform.3

curl_easy_perform - perform a blocking file transfer

#include <curl/curl.h>

CURLcode curl_easy_perform(CURL **/easy_handle/);*

Invoke this function after curl_easy_init(3) and all the curl_easy_setopt(3) calls are made, and it performs the transfer as described in the options. It must be called with the same easy_handle as input as the curl_easy_init(3) call returned.

curl_easy_perform(3) performs the entire request in a blocking manner and returns when done, or earlier if it fails. For non-blocking behavior, see curl_multi_perform(3).

You can do any amount of calls to curl_easy_perform(3) while using the same easy_handle. If you intend to transfer more than one file, you are even encouraged to do so. libcurl will then attempt to re-use the same connection for the following transfers, thus making the operations faster, less CPU intense and using less network resources. Just note that you will have to use curl_easy_setopt(3) between the invokes to set options for the following curl_easy_perform.

You must never call this function simultaneously from two places using the same easy_handle. Let the function return first before invoking it another time. If you want parallel transfers, you must use several curl easy_handles.

A network transfer moves data to a peer or from a peer. An application tells libcurl how to receive data by setting the CURLOPT_WRITEFUNCTION(3) and CURLOPT_WRITEDATA(3) options. To tell libcurl what data to send, there are a few more alternatives but two common ones are CURLOPT_READFUNCTION(3) and CURLOPT_POSTFIELDS(3).

While the easy_handle is added to a multi handle, it cannot be used by curl_easy_perform(3).

  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
    res = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }

Always

CURLE_OK (0) means everything was ok, non-zero means an error occurred as <curl/curl.h> defines - see libcurl-errors(3). If the CURLOPT_ERRORBUFFER(3) was set with curl_easy_setopt(3) there will be a readable error message in the error buffer when non-zero is returned.

*curl_easy_init*(3), *curl_easy_setopt*(3), *curl_multi_add_handle*(3), *curl_multi_perform*(3), *libcurl-errors*(3),