curl/docs/libcurl/opts/CURLINFO_CONDITION_UNMET.md
Viktor Szakats d01d2ec9f1
docs: add CURLOPT type change history, drop casts where present
Some CURLOPT constants defined in the curl public headers were initially
enums (= ints), or macros with bare numeric values. Recent curl releases
upgraded them to `long` constants, to make them pass correctly to
`curl_easy_setop()` by default, i.e. without requiring a `(long)` cast.

This patch drops such casts from the examples embedded in the docs. At
the same time it documents which curl release made them `long` types,
to keep them useful when working with previous libcurl versions.

Also:
- drop a `(long)` cast that was never necessary.
- CURLOPT_ALTSVC_CTRL.md: bump local copy of macros to long.
- test1119: make it ignore symbols ending with an underscore, to skip
  wildcard, e.g. `**CURLAUTH_***`.

Closes #18130
2025-08-02 00:05:33 +02:00

1.9 KiB

c SPDX-License-Identifier Title Section Source See-also Protocol Added-in
Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. curl CURLINFO_CONDITION_UNMET 3 libcurl
CURLOPT_TIMECONDITION (3)
CURLOPT_TIMEVALUE (3)
curl_easy_getinfo (3)
curl_easy_setopt (3)
HTTP
7.19.4

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(3)). 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%

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, 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%

RETURN VALUE

curl_easy_getinfo(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).