#include <curl/curl.h> CURLMcode curl_multi_setopt(CURLM *handle, CURLMOPT_TIMERDATA, void *pointer);
This pointer will not be touched by libcurl but will only be passed in to the timer callbacks's userp argument.
static gboolean timeout_cb(gpointer user_data) { int running; if(user_data) { g_free(user_data); curl_multi_setopt(curl_handle, CURLMOPT_TIMERDATA, NULL); } curl_multi_socket_action(multi, CURL_SOCKET_TIMEOUT, 0, &running); return G_SOURCE_REMOVE; } static int timerfunc(CURLM *multi, long timeout_ms, void *userp) { guint *id = userp; if(id) g_source_remove(*id); /* -1 means we should just delete our timer. */ if(timeout_ms == -1) { g_free(id); id = NULL; } else { if(!id) id = g_new(guint, 1); *id = g_timeout_add(timeout_ms, timeout_cb, id); } curl_multi_setopt(multi, CURLMOPT_TIMERDATA, id); return 0; } curl_multi_setopt(multi, CURLMOPT_TIMERFUNCTION, timerfunc);