CURLOPT_UPLOAD_FLAGS - Man Page

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_UPLOAD_FLAGS, long bitmask);

Pass a long as parameter, which is set to a bitmask, to tell libcurl which flags to send the server relating to uploaded files. The current supported flags are CURLULFLAG_ANSWERED, which sets the Answered flag for IMAP uploads, CURLULFLAG_DELETED, which sets the Deleted flag for IMAP uploads, CURLULFLAG_DRAFT, which sets the Draft flag for IMAP uploads, CURLULFLAG_FLAGGED, which sets the Flagged flag for IMAP uploads, and CURLULFLAG_SEEN, which sets the Seen flag for IMAP uploads.

A bitmask with only the CURLULFLAG_SEEN flag set.

This functionality affects imap and imaps

static size_t read_cb(char *ptr, size_t size, size_t nmemb, void *userdata)
{
  FILE *src = userdata;
  /* copy as much data as possible into the 'ptr' buffer, but no more than
     'size' * 'nmemb' bytes */
  size_t retcode = fread(ptr, size, nmemb, src);

  return retcode;
}

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    FILE *src = fopen("local-file", "r");
    curl_off_t fsize; /* set this to the size of the input file */

    /* we want to use our own read function */
    curl_easy_setopt(curl, CURLOPT_READFUNCTION, read_cb);

    /* enable uploading */
    curl_easy_setopt(curl, CURLOPT_UPLOAD, 1L);

    /* specify target */
    curl_easy_setopt(curl, CURLOPT_URL, "imap://example.com:993/mailbox");

    /* provide username */
    curl_easy_setopt(curl, CURLOPT_USERNAME, "user@example.com");

    /* provide password */
    curl_easy_setopt(curl, CURLOPT_PASSWORD, "password");

    /* specify that uploaded mail should be considered flagged */
    curl_easy_setopt(curl, CURLOPT_UPLOAD_FLAGS, CURLULFLAG_FLAGGED);

    /* now specify which pointer to pass to our callback */
    curl_easy_setopt(curl, CURLOPT_READDATA, src);

    /* Set the size of the file to upload */
    curl_easy_setopt(curl, CURLOPT_INFILESIZE_LARGE, (curl_off_t)fsize);

    /* perform the upload */
    curl_easy_perform(curl);
  }
}

Added in curl 8.13.0

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_UPLOAD(3)

curl_easy_setopt(3), libcurl-symbols(3).