curl_formfree(3)

💅 curl_formfree(3) — free a previously build multipart form post chain

ok so real talk bestie, this is a page from the libcurl Library Functions Manual (yes, that libcurl, the one you've been linking against since forever 🫶), and it's about tidying up after yourself. Let's get into it.

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✨ SYNOPSIS ✨

#include <curl/curl.h>

void curl_formfree(struct curl_httppost *form);

that's the whole vibe. one include, one function, zero drama 💅

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🌸 DESCRIPTION 🌸

okay so first things first, and I need you to hear me on this one:

This function is deprecated. Do not use. 🚨 See curl_mime_init(3) instead. like, genuinely, go look at that one.

curl_formfree() is the little cleanup crew 🧹 for data you previously built/appended with curl_formadd(3). You must call it when the data has been used — and "used" typically means after curl_easy_perform(3) has been called. it's giving "return the shopping cart" energy, ngl.

the pointer you free is the same pointer you passed to the CURLOPT_HTTPPOST(3) option, which is the firstitem pointer from the curl_formadd(3) invoke(s). same one, no copies, iykyk.

form is the pointer as returned from a previous call to curl_formadd(3) and may be NULL.

and if you pass in a NULL pointer in form? the function returns immediately with no action. literally just 👀 and leaves. no crash, no fuss. iconic behaviour honestly.

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🌈 PROTOCOLS 🌈

this functionality affects http only. that's the whole list. http girlies only 💖

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🦋 EXAMPLE 🦋

here's the whole thing in action, bestie — copy it exactly:

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    struct curl_httppost *formpost;
    struct curl_httppost *lastptr;

    /* Fill in a file upload field */
    curl_formadd(&formpost,
                 &lastptr,
                 CURLFORM_COPYNAME, "file",
                 CURLFORM_FILE, "nice-image.jpg",
                 CURLFORM_END);

    curl_easy_setopt(curl, CURLOPT_HTTPPOST, formpost);

    curl_easy_perform(curl);

    /* then cleanup the formpost chain */
    curl_formfree(formpost);
  }
}

see how formpost goes into curl_formadd, then into CURLOPT_HTTPPOST, then finally into curl_formfree? that's the full circle moment 🔥 main character energy from start to finish.

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💀 DEPRECATED 💀

Deprecated in 7.56.0. so yeah. it's a legacy era. respect the history, but move on 🎀

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⭐ AVAILABILITY ⭐

Added in curl 7.1. ancient. vintage. a true elder of the library 👑

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🎀 RETURN VALUE 🎀

None. that's it. nothing comes back. empty handed but at peace 🧚

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💜 SEE ALSO 💜

• curl_formadd(3)
• curl_mime_free(3)
• curl_mime_init(3)

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k that's the page!! stay safe, free your formposts, and please please please use the curl_mime_* family instead 💖

— with love, from the libcurl manual, dated 2026-10-12 🦋✨