curl/docs/libcurl/opts/CURLOPT_RESUME_FROM.md
Daniel Stenberg eefcc1bda4
docs: introduce "curldown" for libcurl man page format
curldown is this new file format for libcurl man pages. It is markdown
inspired with differences:

- Each file has a set of leading headers with meta-data
- Supports a small subset of markdown
- Uses .md file extensions for editors/IDE/GitHub to treat them nicely
- Generates man pages very similar to the previous ones
- Generates man pages that still convert nicely to HTML on the website
- Detects and highlights mentions of curl symbols automatically (when
  their man page section is specified)

tools:

- cd2nroff: converts from curldown to nroff man page
- nroff2cd: convert an (old) nroff man page to curldown
- cdall: convert many nroff pages to curldown versions
- cd2cd: verifies and updates a curldown to latest curldown

This setup generates .3 versions of all the curldown versions at build time.

CI:

Since the documentation is now technically markdown in the eyes of many
things, the CI runs many more tests and checks on this documentation,
including proselint, link checkers and tests that make sure we capitalize the
first letter after a period...

Closes #12730
2024-01-23 00:29:02 +01:00

1.7 KiB

c SPDX-License-Identifier Title Section Source See-also
Copyright (C) Daniel Stenberg, <daniel.se>, et al. curl CURLOPT_RESUME_FROM 3 libcurl
CURLOPT_INFILESIZE (3)
CURLOPT_RANGE (3)
CURLOPT_RESUME_FROM_LARGE (3)

NAME

CURLOPT_RESUME_FROM - offset to resume transfer from

SYNOPSIS

#include <curl/curl.h>

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

DESCRIPTION

Pass a long as parameter. It contains the offset in number of bytes that you want the transfer to start from. Set this option to 0 to make the transfer start from the beginning (effectively disabling resume). For FTP, set this option to -1 to make the transfer start from the end of the target file (useful to continue an interrupted upload).

When 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 to the remote target file.

If you need to resume a transfer beyond the 2GB limit, use CURLOPT_RESUME_FROM_LARGE(3) instead.

DEFAULT

0, not used

PROTOCOLS

HTTP, FTP, SFTP, FILE

EXAMPLE

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

    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);
  }
}

AVAILABILITY

Always

RETURN VALUE

Returns CURLE_OK