Authenticating libcurl FTP download in C++ - c++

Question

I am trying to upload a file using libcurl but it appears that it is not authenticating the connection to my server. I have tried using the ftp://username:password#example.com/ but to no avail. This is my code:
#include <stdio.h>
#include <string.h>
#include <curl/curl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#ifdef WIN32
#include <io.h>
#else
#include <unistd.h>
#endif
#define LOCAL_FILE "C:/myfile.txt"
#define UPLOAD_FILE_AS "file.txt"
#define REMOTE_URL "ftp://example.com/" UPLOAD_FILE_AS
#define RENAME_FILE_TO "file.txt"
static size_t read_callback(void *ptr, size_t size, size_t nmemb, void *stream)
{
curl_off_t nread;
size_t retcode = fread(ptr, size, nmemb, (FILE *) stream);
nread = (curl_off_t) retcode;
fprintf(stderr, "*** We read %" CURL_FORMAT_CURL_OFF_T " bytes from filen", nread);
return retcode;
}
int main(void)
{
CURL *curl;
CURLcode res;
FILE *hd_src;
struct stat file_info;
curl_off_t fsize;
struct curl_slist *headerlist = NULL;
static const char buf_1[] = "RNFR " UPLOAD_FILE_AS;
static const char buf_2[] = "RNTO " RENAME_FILE_TO;
if (stat(LOCAL_FILE, &file_info)) {
printf("Couldnt open '%s': %sn", LOCAL_FILE, strerror(errno));
return 1;
}
fsize = (curl_off_t) file_info.st_size;
printf("Local file size: %" CURL_FORMAT_CURL_OFF_T " bytes.n", fsize);
hd_src = fopen(LOCAL_FILE, "rb");
curl_global_init(CURL_GLOBAL_ALL);
curl = curl_easy_init();
if (curl) {
headerlist = curl_slist_append(headerlist, buf_1);
headerlist = curl_slist_append(headerlist, buf_2);
curl_easy_setopt(curl, CURLOPT_READFUNCTION, read_callback);
curl_easy_setopt(curl, CURLOPT_UPLOAD, 1L);
curl_easy_setopt(curl, CURLOPT_URL, REMOTE_URL);
curl_easy_setopt(curl, CURLOPT_POSTQUOTE, headerlist);
curl_easy_setopt(curl, CURLOPT_READDATA, hd_src);
curl_easy_setopt(curl, CURLOPT_INFILESIZE_LARGE, (curl_off_t) fsize);
res = curl_easy_perform(curl);
curl_slist_free_all(headerlist);
/* always cleanup */
curl_easy_cleanup(curl);
}
fclose(hd_src); /* close the local file */
curl_global_cleanup();
return 0;
}

Answer 1

You have to pass the required username and password to libcurl. This is done via the option CURLOPT_USERPWD, just set it as follows:
curl_easy_setopt( curl, CURLOPT_USERPWD, "username:password" );