CURLOPT_KEEP_SENDING_ON_ERROR - keep sending on early HTTP response >= 300

Added in curl 7.51.0

0, stop sending on error

A long parameter set to 1 tells the library to keep sending the request body if the HTTP code returned is equal to or larger than 300. The default action would be to stop sending and close the stream or connection. This option is suitable for manual NTLM authentication, i.e. if an application does not use CURLOPT_HTTPAUTH(3), but instead sets "Authorization: NTLM ..." headers manually using CURLOPT_HTTPHEADER(3). Most applications do not need this option.

int main(void) { CURL *curl = curl_easy_init(); if(curl) { CURLcode ret; curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/"); curl_easy_setopt(curl, CURLOPT_POSTFIELDS, "sending data"); curl_easy_setopt(curl, CURLOPT_KEEP_SENDING_ON_ERROR, 1L); ret = curl_easy_perform(curl); } }

CURLOPT_KEEP_SENDING_ON_ERROR - keep sending on early HTTP response >= 300

This functionality affects http only

curl_easy_setopt(3) returns a CURLcode indicating success or error. CURLE_OK (0) means everything was OK, non-zero means an error occurred, see libcurl-errors(3).

CURLINFO_RESPONSE_CODE(3), CURLOPT_FAILONERROR(3), CURLOPT_HTTPHEADER(3) libcurl 2025-06-16 CURLOPT_KEEP_SENDING_ON_ERROR(3)

#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_KEEP_SENDING_ON_ERROR, long keep_sending);