curl_mime_data(3)

💅 curl_mime_data — bestie, it's the curl_mime_data(3) page from the Library Functions Manual ✨

okay so real talk, this one is a little icon. it's a libcurl function (you know, the C library situation 🎀) and it does exactly one job: it slaps some body data from your memory straight onto a mime part. that's it. that's the whole gig. queen behavior honestly 👑

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🌸 NAME 🌸

curl_mime_data — set a mime part's body data from memory. no cap, that's literally it 💖

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✨ SYNOPSIS ✨

#include <curl/curl.h>

CURLcode curl_mime_data(curl_mimepart *part, const char *data,
                        size_t datasize);

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🦋 DESCRIPTION 🦋

so curl_mime_data(3) sets a mime part's body content, and the content comes from memory data. very much "here's my bytes, go off" energy 💅

Let's break the args down because we respect clarity in this house:

• part is the mime part you're assigning contents to. it's the one you already made with curl_mime_addpart(3). don't skip that step bestie, you need the part to exist first 🫶
• data points to the data, and this function copies it. so the storage is yours again the moment the call returns — reuse it freely, it's giving "no strings attached" ✨
• datasize is the number of bytes that data points to. you can also set it to CURL_ZERO_TERMINATED to say "hey, data is a null-terminated character string" and let it figure out the length itself 🎀

Setting a part's contents multiple times is totally valid — only the value from the last call is retained. last one wins, main character energy 👑 and if you want to unassign a part's contents entirely, just set data to NULL. poof, gone, no notes 💀

⚠️ real talk: setting large data is memory consuming. if your data is chonky, you might wanna consider curl_mime_data_cb(3) instead. it's the cooler option for big stuff, iykyk 🍓

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🌈 PROTOCOLS 🌈

This functionality affects http, imap and smtp. the trio. periodt 💜

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🎀 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);

    /* add data to the part  */
    curl_mime_data(part, "raw contents to send", CURL_ZERO_TERMINATED);
  }
}

look at that flow 😭 init the handle, add a part, feed it data. three steps, zero drama. we love a clean pipeline 🌸

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⭐ AVAILABILITY ⭐

Added in curl 7.56.0. so if you're on something older than that... bestie. upgrade. respectfully 🙈

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💖 RETURN VALUE 💖

This function returns a CURLcode indicating success or error — classic libcurl move.

• CURLE_OK (0) means everything was OK. slay, we're so back 🎉
• non-zero means an error occurred, and you should go check libcurl-errors(3) for the tea 🔥

and lowkey important: 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. so when it goes wrong you actually get lore 💀📖

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👑 SEE ALSO 👑

• curl_mime_addpart(3)
• curl_mime_data_cb(3)
• curl_mime_name(3)
• curl_mime_type(3)

the whole mime friend group, go say hi 🫶

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k bye, this page was brought to you by libcurl, dated 2026-10-12, and its original title was curl_mime_data(3) — thanks for reading bestie, go set some mime data, you're gonna do amazing 🌈💅✨