CURLOPT_TRAILERDATA - pointer passed to trailing headers callback

Added in curl 7.64.0

NULL

Data pointer to be passed to the HTTP trailer callback function.

struct MyData { void *custom; }; int main(void) { CURL *curl = curl_easy_init(); if(curl) { struct MyData data; curl_easy_setopt(curl, CURLOPT_TRAILERDATA, &data); } }

CURLOPT_TRAILERDATA - pointer passed to trailing headers callback

This functionality affects http only

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_TRAILERFUNCTION(3), CURLOPT_WRITEFUNCTION(3) libcurl 2025-06-16 CURLOPT_TRAILERDATA(3)

#include <curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_TRAILERDATA, void *userdata);