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Diffstat (limited to 'docs/libcurl/opts/GNURLOPT_RESOLVER_START_FUNCTION.3')
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1 files changed, 83 insertions, 0 deletions
diff --git a/docs/libcurl/opts/GNURLOPT_RESOLVER_START_FUNCTION.3 b/docs/libcurl/opts/GNURLOPT_RESOLVER_START_FUNCTION.3 new file mode 100644 index 000000000..9adcfca89 --- /dev/null +++ b/docs/libcurl/opts/GNURLOPT_RESOLVER_START_FUNCTION.3 @@ -0,0 +1,83 @@ +.\" ************************************************************************** +.\" * _ _ ____ _ +.\" * Project ___| | | | _ \| | +.\" * / __| | | | |_) | | +.\" * | (__| |_| | _ <| |___ +.\" * \___|\___/|_| \_\_____| +.\" * +.\" * Copyright (C) 1998 - 2018, Daniel Stenberg, <daniel@haxx.se>, et al. +.\" * +.\" * This software is licensed as described in the file COPYING, which +.\" * you should have received as part of this distribution. The terms +.\" * are also available at https://curl.haxx.se/docs/copyright.html. +.\" * +.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell +.\" * copies of the Software, and permit persons to whom the Software is +.\" * furnished to do so, under the terms of the COPYING file. +.\" * +.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY +.\" * KIND, either express or implied. +.\" * +.\" ************************************************************************** +.\" +.TH GNURLOPT_RESOLVER_START_FUNCTION 3 "14 Feb 2018" "libcurl 7.59.0" "curl_easy_setopt options" +.SH NAME +CURLOPT_RESOLVER_START_FUNCTION \- set callback to be called before a new resolve request is started +.SH SYNOPSIS +.nf +#include <gnurl/curl.h> + +int resolver_start_cb(void *resolver_state, void *reserved, void *userdata); + +CURLcode curl_easy_setopt(CURL *handle, + CURLOPT_RESOLVER_START_FUNCTION, + resolver_start_cb); +.SH DESCRIPTION +Pass a pointer to your callback function, which should match the prototype +shown above. + +This callback function gets called by libcurl every time before a new resolve +request is started. + +\fIresolver_state\fP points to a backend-specific resolver state. Currently +only the ares resolver backend has a resolver state. It can be used to set up +any desired option on the ares channel before it's used, for example setting up +socket callback options. + +\fIreserved\fP is reserved. + +\fIuserdata\fP is the user pointer set with the +\fICURLOPT_RESOLVER_START_DATA(3)\fP option. + +The callback must return 0 on success. Returning a non-zero value will cause +the resolve to fail. +.SH DEFAULT +NULL (No callback) +.SH PROTOCOLS +All +.SH EXAMPLE +.nf +static int resolver_start_cb(void *resolver_state, void *reserved, + void *userdata) +{ + (void)reserved; + printf("Received resolver_state=%p userdata=%p\\n", + resolver_state, userdata); + return 0; +} + +CURL *curl = curl_easy_init(); +if(curl) { + curl_easy_setopt(curl, CURLOPT_RESOLVER_START_FUNCTION, resolver_start_cb); + curl_easy_setopt(curl, CURLOPT_RESOLVER_START_DATA, curl); + curl_easy_setopt(curl, CURLOPT_URL, "http://example.com"); + curl_easy_perform(curl); + curl_easy_cleanup(curl); +} +.fi +.SH AVAILABILITY +Added in 7.59.0 +.SH RETURN VALUE +Returns CURLE_OK +.SH "SEE ALSO" +.BR CURLOPT_RESOLVER_START_DATA "(3) " |