CURLOPT_PROGRESSDATA - pointer passed to the progress callback

Added in curl 7.1

NULL

Pass a pointer that is untouched by libcurl and passed as the first argument in the progress callback set with CURLOPT_PROGRESSFUNCTION(3).

struct progress { char *private; size_t size; }; static int progress_callback(void *clientp, double dltotal, double dlnow, double ultotal, double ulnow) { struct progress *memory = clientp; printf("private: %p\n", memory->private); /* use the values */ return 0; /* all is good */ } int main(void) { CURL *curl = curl_easy_init(); if(curl) { struct progress data; /* pass struct to callback */ curl_easy_setopt(curl, CURLOPT_PROGRESSDATA, &data); curl_easy_setopt(curl, CURLOPT_PROGRESSFUNCTION, progress_callback); curl_easy_perform(curl); } }

CURLOPT_PROGRESSDATA - pointer passed to the progress callback

This functionality affects all supported protocols

curl_easy_setopt(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).

CURLOPT_PROGRESSFUNCTION(3), CURLOPT_XFERINFOFUNCTION(3) libcurl 2025-06-16 CURLOPT_PROGRESSDATA(3)

#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROGRESSDATA, void *pointer);