Annotation of embedaddon/curl/docs/libcurl/opts/CURLOPT_DNS_SHUFFLE_ADDRESSES.3, revision 1.1.1.1
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23: .TH CURLOPT_DNS_SHUFFLE_ADDRESSES 3 "March 17, 2018" "libcurl 7.70.0" "curl_easy_setopt options"
24:
25: .SH NAME
26: CURLOPT_DNS_SHUFFLE_ADDRESSES \- Shuffle addresses when a hostname returns more than one
27: .SH SYNOPSIS
28: .nf
29: #include <curl/curl.h>
30:
31: CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DNS_SHUFFLE_ADDRESSES, long onoff);
32: .fi
33: .SH DESCRIPTION
34: When a name is resolved and more than one IP address is returned, shuffle the
35: order of all returned addresses so that they will be used in a random order.
36: This is similar to the ordering behavior of gethostbyname which is no longer
37: used on most platforms.
38:
39: Addresses will not be reshuffled if a name resolution is completed using the
40: DNS cache. \fICURLOPT_DNS_CACHE_TIMEOUT(3)\fP can be used together with this
41: option to reduce DNS cache timeout or disable caching entirely if frequent
42: reshuffling is needed.
43:
44: Since the addresses returned will be reordered randomly, their order will not
45: be in accordance with RFC 3484 or any other deterministic order that may be
46: generated by the system's name resolution implementation. This may have
47: performance impacts and may cause IPv4 to be used before IPv6 or vice versa.
48: .SH DEFAULT
49: 0 (disabled)
50: .SH PROTOCOLS
51: All
52: .SH EXAMPLE
53: .nf
54: CURL *curl = curl_easy_init();
55: if(curl) {
56: curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
57: curl_easy_setopt(curl, CURLOPT_DNS_SHUFFLE_ADDRESSES, 1L);
58:
59: curl_easy_perform(curl);
60:
61: /* always cleanup */
62: curl_easy_cleanup(curl);
63: }
64: .fi
65: .SH AVAILABILITY
66: Added in 7.60.0
67: .SH RETURN VALUE
68: CURLE_OK or an error such as CURLE_UNKNOWN_OPTION.
69: .SH "SEE ALSO"
70: .BR CURLOPT_DNS_CACHE_TIMEOUT "(3), " CURLOPT_IPRESOLVE "(3), "
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