curl\_mime\_type(3) Library Functions Manual curl\_mime\_type(3)

# [NAME](#NAME)

curl\_mime\_type - set a mime part's content type

# [SYNOPSIS](#SYNOPSIS)

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

# [DESCRIPTION](#DESCRIPTION)

[*curl\_mime\_type(3)*](/man/os/curl/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](#PROTOCOLS)

This functionality affects http, imap and smtp

# [EXAMPLE](#EXAMPLE)

```
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");
}
}
```

# [AVAILABILITY](#AVAILABILITY)

Added in curl 7.56.0

# [RETURN VALUE](#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)*](/man/os/curl/libcurl-errors.3). If [*CURLOPT\_ERRORBUFFER(3)*](/man/os/curl/CURLOPT_ERRORBUFFER.3) was set with [*curl\_easy\_setopt(3)*](/man/os/curl/curl_easy_setopt.3) there can be an error message stored in the error buffer when non-zero is returned.

# [SEE ALSO](#SEE_ALSO)

[**curl\_mime\_addpart**(3)](/man/os/curl/curl_mime_addpart.3), [**curl\_mime\_data**(3)](/man/os/curl/curl_mime_data.3), [**curl\_mime\_name**(3)](/man/os/curl/curl_mime_name.3)

2026-10-19 libcurl

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Document: curl_mime_type(3) from curl 8.23.0-r1 (Chainguard OS)
Source: https://github.com/curl/curl.git