curl_mime_type(3)

curl_mime_type3

Set a mime part's content type

Usage

#include <curl/curl.h>
CURLcode curl_mime_type(curl_mimepart *part, const char *mimetype);

Overview

curl_mime_type(3) sets a mime part's content type.

part is the part's handle to assign the content type to.

mimetype points to the null-terminated file mime type string; it may be set to NULL to remove a previously attached mime type.

The mime type string is copied into the part, thus the associated storage may safely be released or reused after call. Setting a part's type multiple times is valid: only the value set by the last call is retained.

In the absence of a mime type and if needed by the protocol specifications, a default mime type is determined by the context:

- If set as a custom header, use this value.

- application/form-data for an HTTP form post.

- If a remote filename is set, the mime type is taken from the filename extension, or application/octet-stream by default.

- For a multipart part, multipart/mixed.

- text/plain in other cases.

Protocols

This functionality affects http, imap and smtp

Examples

int main(void)
{
  curl_mime *mime;
  curl_mimepart *part;
  CURL *curl = curl_easy_init();
  if(curl) {
    /* create a mime handle */
    mime = curl_mime_init(curl);
    /* add a part */
    part = curl_mime_addpart(mime);
    /* get data from this file */
    curl_mime_filedata(part, "image.png");
    /* content-type for this part */
    curl_mime_type(part, "image/png");
    /* set name */
    curl_mime_name(part, "image");
}
}

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.

Releases

5 releases since Debian 10 (Buster); the text changed 4 times.

  1. 10
  2. 11
  3. 12
  4. 13
  5. Arch

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.