carta
curl_mime_subparts(3)

curl_mime_subparts3

Set sub-parts of a multipart mime part

Usage

CURLcode curl_mime_subparts(curl_mimepart *part, curl_mime *subparts);

Overview

curl_mime_subparts(3) sets a multipart mime part's content from a mime structure.

part is a handle to the multipart part.

subparts is a mime structure handle holding the sub-parts. After curl_mime_subparts(3) succeeds, the mime structure handle belongs to the multipart part and must not be freed explicitly. It may however be updated by subsequent calls to mime API functions.

Setting a part's contents multiple times is valid: only the value set by the last call is retained. It is possible to unassign previous part's contents by setting subparts to NULL.

Protocols

This functionality affects http, imap and smtp

Examples

static const char *inline_html = "<title>example</title>";
static const char *inline_text = "once upon the time";
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    struct curl_slist *slist;
    /* The inline part is an alternative proposing the html and the text
       versions of the email. */
    curl_mime *alt = curl_mime_init(curl);
    curl_mimepart *part;
    /* HTML message. */
    part = curl_mime_addpart(alt);
    curl_mime_data(part, inline_html, CURL_ZERO_TERMINATED);
    curl_mime_type(part, "text/html");
    /* Text message. */
    part = curl_mime_addpart(alt);
    curl_mime_data(part, inline_text, CURL_ZERO_TERMINATED);
    /* Create the inline part. */
    part = curl_mime_addpart(alt);
    curl_mime_subparts(part, alt);
    curl_mime_type(part, "multipart/alternative");
    slist = curl_slist_append(NULL, "Content-Disposition: inline");
    curl_mime_headers(part, slist, 1);
  }
}

Return value

This function returns a CURLcode indicating success or error.

CURLE_OK (0) means everything was OK, non-zero means an error occurred, see libcurl-errors(3). If CURLOPT_ERRORBUFFER(3) was set with curl_easy_setopt(3) there can be an error message stored in the error buffer when non-zero is returned.

History

  • Arch Linux 2026-11-01: the text shown here
  • Debian 13 (Trixie)
  • Debian 12 (Bookworm)
  • Debian 11 (Bullseye)
  • Debian 10 (Buster)

Availability

Added in curl 7.56.0

From curl 8.23.0-1 in Arch Linux 2026-11-01. Parsed by carta from the page's man source.