curl/docs/libcurl/opts/CURLOPT_FTP_USE_EPSV.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

1.6 KiB

c SPDX-License-Identifier Title Section Source See-also
Copyright (C) Daniel Stenberg, <daniel.se>, et al. curl CURLOPT_FTP_USE_EPSV 3 libcurl
CURLOPT_FTPPORT (3)
CURLOPT_FTP_USE_EPRT (3)

NAME

CURLOPT_FTP_USE_EPSV - use EPSV for FTP

SYNOPSIS

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_FTP_USE_EPSV, long epsv);

DESCRIPTION

Pass epsv as a long. If the value is 1, it tells curl to use the EPSV command when doing passive FTP downloads (which it does by default). Using EPSV means that libcurl first attempts to use the EPSV command before using PASV. If you pass zero to this option, it does not use EPSV, only plain PASV.

The EPSV command is a slightly newer addition to the FTP protocol than PASV and is the preferred command to use since it enables IPv6 to be used. Old FTP servers might not support it, which is why libcurl has a fallback mechanism. Sometimes that fallback is not enough and then this option might come handy.

If the server is an IPv6 host, this option has no effect.

DEFAULT

1

PROTOCOLS

FTP

EXAMPLE

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
    curl_easy_setopt(curl, CURLOPT_URL,
                     "ftp://example.com/old-server/file.txt");

    /* let's shut off this modern feature */
    curl_easy_setopt(curl, CURLOPT_FTP_USE_EPSV, 0L);

    res = curl_easy_perform(curl);

    curl_easy_cleanup(curl);
  }
}

AVAILABILITY

Along with FTP

RETURN VALUE

Returns CURLE_OK if FTP is supported, and CURLE_UNKNOWN_OPTION if not.