#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_RESUME_FROM_LARGE, curl_off_t from);
When doing uploads with FTP, the resume position is where in the local/source file libcurl should try to resume the upload from and it will then append the source file to the remote target file.
CURL *curl = curl_easy_init(); if(curl) { curl_off_t resume_position = GET_IT_SOMEHOW; curl_off_t file_size = GET_IT_SOMEHOW_AS_WELL; curl_easy_setopt(curl, CURLOPT_URL, "ftp://example.com"); /* resuming upload at this position, possibly beyond 2GB */ curl_easy_setopt(curl, CURLOPT_RESUME_FROM_LARGE, resume_position); /* ask for upload */ curl_easy_setopt(curl, CURLOPT_UPLOAD, 1L); /* set total data amount to expect */ curl_easy_setopt(curl, CURLOPT_INFILESIZE_LARGE, file_size); /* Perform the request */ curl_easy_perform(curl); }