CURLINFO_CONDITION_UNMET explained

Name

CURLINFO_CONDITION_UNMET - get info on unmet time conditional or 304 HTTP response.

Synopsis

#include <curl/curl.h>
 
CURLcode curl_easy_getinfo(CURL *handle, CURLINFO_CONDITION_UNMET,
                           long *unmet);

Description

Pass a pointer to a long to receive the number 1 if the condition provided in the previous request did not match (see CURLOPT_TIMECONDITION). Alas, if this returns a 1 you know that the reason you did not get data in return is because it did not fulfill the condition. The long this argument points to gets a zero stored if the condition instead was met. This can also return 1 if the server responded with a 304 HTTP status code, for example after sending a custom "If-Match-*" header.

Protocols

This functionality affects http only

Example

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
 
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
 
    /* January 1, 2020 is 1577833200 */
    curl_easy_setopt(curl, CURLOPT_TIMEVALUE, 1577833200L);
 
    /* If-Modified-Since the above time stamp */
    curl_easy_setopt(curl, CURLOPT_TIMECONDITION,
                     (long)CURL_TIMECOND_IFMODSINCE);
 
    /* Perform the request */
    res = curl_easy_perform(curl);
 
    if(!res) {
      /* check the time condition */
      long unmet;
      res = curl_easy_getinfo(curl, CURLINFO_CONDITION_UNMET, &unmet);
      if(!res) {
        printf("The time condition was %sfulfilled\n", unmet?"NOT":"");
      }
    }
  }
}

Availability

Added in curl 7.19.4

Return value

curl_easy_getinfo returns a CURLcode indicating success or error.

CURLE_OK (0) means everything was OK, non-zero means an error occurred, see libcurl-errors.