curl_easy_perform - perform a blocking network transfer

Name

curl_easy_perform - perform a blocking network transfer

Synopsis

#include <curl/curl.h>
 
CURLcode curl_easy_perform(CURL *easy_handle);

Description

curl_easy_perform performs a network transfer in a blocking manner and returns when done, or earlier if it fails. For non-blocking behavior, see curl_multi_perform.

Invoke this function after curl_easy_init and all the curl_easy_setopt 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 call returned.

You can do any amount of calls to curl_easy_perform while using the same easy_handle. If you intend to transfer more than one file, you are even encouraged to do so. libcurl attempts to reuse existing connections for the following transfers, thus making the operations faster, less CPU intense and using less network resources. You probably want to use curl_easy_setopt between the invokes to set options for the following curl_easy_perform call.

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 and CURLOPT_WRITEDATA options. To tell libcurl what data to send, there are a few more alternatives but two common ones are CURLOPT_READFUNCTION and CURLOPT_POSTFIELDS.

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

Protocols

This functionality affects all supported protocols

Example

int main(void)
{
  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);
  }
}

Availability

Added in curl 7.1

Return value

This function returns a CURLcode indicating success or error.

CURLE_OK (0) means everything was OK, non-zero means an error occurred, see libcurl-errors. If CURLOPT_ERRORBUFFER was set with curl_easy_setopt there can be an error message stored in the error buffer when non-zero is returned.

See also

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

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