GNURLOPT_HEADERDATA(3)

🌸 GNURLOPT_HEADERDATA(3) 🌸

okay so this page is from the curl_easy_setopt options manual, and it's all about GNURLOPT_HEADERDATA(3) — yes bestie, the header-data pointer situation. let's get into it 💅

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✨ NAME ✨

CURLOPT_HEADERDATA — pointer to pass to header callback 🫶

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🦋 SYNOPSIS 🦋

#include <gnurl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HEADERDATA, void
*pointer);

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💖 DESCRIPTION 💖

You pass a pointer in, and that pointer is used to write the header part of the received data to. literally that's its whole job ✨

If you're using CURLOPT_WRITEFUNCTION(3) or CURLOPT_HEADERFUNCTION(3), then that pointer gets passed in to the matching callback. your callback can do its thing with it, iykyk 💫

If neither of those options is set, then pointer must be a valid FILE *, and a plain fwrite() will use it to write headers to. no cap, that's the requirement 🙈

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🎀 DEFAULT 🎀

NULL

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🌈 PROTOCOLS 🌈

All — every single one, slay 💅

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🔥 EXAMPLE 🔥

struct my_info {
  int shoesize;
  char *secret;
};

static size_t header_callback(char *buffer, size_t size,
                              size_t nitems, void *userdata)
{
  struct my_info *i = (struct my_info *)userdata;

  /* now this callback can access the my_info struct */

  return nitems * size;
}

CURL *curl = curl_easy_init();
if(curl) {
  struct my_info my = { 10, "the cookies are in the cupboard" };
  curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");

  curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, header_callback);

  /* pass in custom data to the callback */
  curl_easy_setopt(curl, CURLOPT_HEADERDATA, &my);

  curl_easy_perform(curl);
}

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⭐ AVAILABILITY ⭐

Always — like, always always 👑

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👑 RETURN VALUE 👑

Returns CURLE_OK 🎀

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🫶 SEE ALSO 🫶

• CURLOPT_HEADERFUNCTION(3)
• CURLOPT_WRITEFUNCTION(3)

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mwah 💋 this page is from libcurl 7.37.0, dated 17 Jun 2014 — bye bestie, go pass that pointer with main character energy 🌟