CURLOPT_RESUME_FROM(3)

💅 CURLOPT_RESUME_FROM 💅

okay so bestie, this is a page from the libcurl manual — the CURLOPT_RESUME_FROM(3) one — and it's literally about picking the byte offset your transfer resumes from. slay. let's get into it 🫶

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✨ NAME ✨

CURLOPT_RESUME_FROM — the offset to resume a transfer from 🎀

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🌸 SYNOPSIS 🌸

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_RESUME_FROM, long from);

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🦋 DESCRIPTION 🦋

So you pass in a long as the parameter, right? That's your offset — in number of bytes — for where you want the transfer to start from. lowkey simple 💅

Set this option to 0 and the transfer starts from the very beginning, which effectively disables resume. icon energy, back to square one.

For FTP specifically, set this option to -1 and the transfer starts from the end of the target file — which is genuinely so useful for continuing an interrupted upload. no cap 🔥

When you're doing uploads with FTP, the resume position is where in the local/source file libcurl should try to resume the upload from, and it then appends the source file onto the remote target file. the way that works is honestly so clean.

💀 one thing though: if you need to resume a transfer beyond the 2GB limit, use CURLOPT_RESUME_FROM_LARGE(3) instead. don't come crying to this option, it can't help you there.

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🎀 DEFAULT 🎀

0, not used

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🌈 PROTOCOLS 🌈

This functionality affects all supported protocols ✨ (yes, all of them, main character behaviour)

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🍓 EXAMPLE 🍓

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    long size_of_file = 6789;

    curl_easy_setopt(curl, CURLOPT_URL, "ftp://example.com");

    /* resume upload at byte index 200 */
    curl_easy_setopt(curl, CURLOPT_RESUME_FROM, 200L);

    /* ask for upload */
    curl_easy_setopt(curl, CURLOPT_UPLOAD, 1L);

    /* set total data amount to expect */
    curl_easy_setopt(curl, CURLOPT_INFILESIZE, size_of_file);

    /* Perform the request */
    curl_easy_perform(curl);
  }
}

like, look at her go 😭💖 byte index 200, uploading, total size set, request performed. ate.

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⭐ AVAILABILITY ⭐

Added in curl 7.1 — she's been around a minute, a real veteran 👑

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💜 RETURN VALUE 💜

curl_easy_setopt(3) returns a CURLcode indicating success or error.

CURLE_OK (0) means everything was OK. non-zero means an error occurred — go check libcurl-errors(3) for the tea 🙈

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👑 SEE ALSO 👑

• CURLOPT_INFILESIZE(3)
• CURLOPT_RANGE(3)
• CURLOPT_RESUME_FROM_LARGE(3)

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and that's the whole page, bestie 🧚💫 this one came from the libcurl manual, dated 2026-10-12, and it's the CURLOPT_RESUME_FROM(3) page. go resume something iconic 💅✨