#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/** This example shows an FTP upload, with a rename of the file just after* a successful upload.** Example based on source code provided by Erick Nuwendam. Thanks!*/#define LOCAL_FILE      "main.c"
#define UPLOAD_FILE_AS  "wkl.c"
#define REMOTE_URL      "ftp://127.0.0.1/"  UPLOAD_FILE_AS
#define RENAME_FILE_TO  "haaaa.c"
#define USERPASSWD      "nobody:lampp"/* NOTE: if you want this example to work on Windows with libcurl as aDLL, you MUST also provide a read callback with CURLOPT_READFUNCTION.Failing to do so will give you a crash since a DLL may not use thevariable's memory when passed in to it from an app like this. */
static size_t read_callback(void *ptr, size_t size, size_t nmemb, void *stream)
{curl_off_t nread;/* in real-world cases, this would probably get this data differentlyas this fread() stuff is exactly what the library already would doby default internally */size_t retcode = fread(ptr, size, nmemb, stream);nread = (curl_off_t)retcode;fprintf(stderr, "*** We read %" CURL_FORMAT_CURL_OFF_T" bytes from file\n", 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;/* get the file size of the local file */if(stat(LOCAL_FILE, &file_info)) {printf("Couldnt open '%s': %s\n", 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);/* get a FILE * of the same file */hd_src = fopen(LOCAL_FILE, "rb");/* In windows, this will init the winsock stuff */curl_global_init(CURL_GLOBAL_ALL);/* get a curl handle */curl = curl_easy_init();if(curl) {/* build a list of commands to pass to libcurl */     headerlist = curl_slist_append(headerlist, buf_1);headerlist = curl_slist_append(headerlist, buf_2);curl_easy_setopt(curl, CURLOPT_USERPWD, USERPASSWD);    /* we want to use our own read function */curl_easy_setopt(curl, CURLOPT_READFUNCTION, read_callback);/* enable uploading */curl_easy_setopt(curl, CURLOPT_UPLOAD, 1L);/* specify target */curl_easy_setopt(curl,CURLOPT_URL, REMOTE_URL);/* pass in that last of FTP commands to run after the transfer */curl_easy_setopt(curl, CURLOPT_POSTQUOTE, headerlist);/* now specify which file to upload */curl_easy_setopt(curl, CURLOPT_READDATA, hd_src);/* Set the size of the file to upload (optional).  If you give a *_LARGEoption you MUST make sure that the type of the passed-in argument is acurl_off_t. If you use CURLOPT_INFILESIZE (without _LARGE) you mustmake sure that to pass in a type 'long' argument. */curl_easy_setopt(curl, CURLOPT_INFILESIZE_LARGE,(curl_off_t)fsize);/* Now run off and do what you've been told! */res = curl_easy_perform(curl);/* clean up the FTP commands list */curl_slist_free_all (headerlist);/* always cleanup */curl_easy_cleanup(curl);}fclose(hd_src); /* close the local file */curl_global_cleanup();return 0;
}

gcc -g main.c -o curl -lcurl

 ./curl
Local file size: 1762 bytes.
*** We read 1762 bytes from file