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CURLOPT_RESOLVER_START_FUNCcurl_easy_setopt CURLOPT_RESOLVER_START_FUNCTION(3) NAME CURLOPT_RESOLVER_START_FUNCTION - set callback to be called before a new resolve request is started SYNOPSIS #include <curl/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); DESCRIPTION Pass a pointer to your callback function, which should match the proto- type shown above. This callback function gets called by libcurl every time before a new resolve request is started. resolver_state 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 ex- ample setting up socket callback options. reserved is reserved. userdata is the user pointer set with the CURLOPT_RE- SOLVER_START_DATA(3) option. The callback must return 0 on success. Returning a non-zero value will cause the resolve to fail. DEFAULT NULL (No callback) PROTOCOLS All EXAMPLE 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); } AVAILABILITY Added in 7.59.0 RETURN VALUE Returns CURLE_OK SEE ALSO CURLOPT_RESOLVER_START_DATA(3) libcurl 7.72.0 February 14, CURLOPT_RESOLVER_START_FUNCTION(3)
NAME | SYNOPSIS | DESCRIPTION | DEFAULT | PROTOCOLS | EXAMPLE | AVAILABILITY | RETURN VALUE | SEE ALSO
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