curl/docs/libcurl/opts/CURLOPT_FTP_SSL_CCC.md
Viktor Szakats d01d2ec9f1
docs: add CURLOPT type change history, drop casts where present
Some CURLOPT constants defined in the curl public headers were initially
enums (= ints), or macros with bare numeric values. Recent curl releases
upgraded them to `long` constants, to make them pass correctly to
`curl_easy_setop()` by default, i.e. without requiring a `(long)` cast.

This patch drops such casts from the examples embedded in the docs. At
the same time it documents which curl release made them `long` types,
to keep them useful when working with previous libcurl versions.

Also:
- drop a `(long)` cast that was never necessary.
- CURLOPT_ALTSVC_CTRL.md: bump local copy of macros to long.
- test1119: make it ignore symbols ending with an underscore, to skip
  wildcard, e.g. `**CURLAUTH_***`.

Closes #18130
2025-08-02 00:05:33 +02:00

85 lines
1.8 KiB
Markdown

---
c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
SPDX-License-Identifier: curl
Title: CURLOPT_FTP_SSL_CCC
Section: 3
Source: libcurl
Protocol:
- FTP
See-also:
- CURLOPT_FTPSSLAUTH (3)
- CURLOPT_PROTOCOLS_STR (3)
- CURLOPT_USE_SSL (3)
Added-in: 7.16.1
---
# NAME
CURLOPT_FTP_SSL_CCC - switch off SSL again with FTP after auth
# SYNOPSIS
~~~c
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_FTP_SSL_CCC,
long how);
~~~
# DESCRIPTION
If enabled, this option makes libcurl use CCC (Clear Command Channel). It
shuts down the SSL/TLS layer after authenticating. The rest of the control
channel communication remains unencrypted. This allows NAT routers to follow
the FTP transaction. Pass a long using one of the values below
## CURLFTPSSL_CCC_NONE
do not attempt to use CCC.
## CURLFTPSSL_CCC_PASSIVE
Do not initiate the shutdown, but wait for the server to do it. Do not send a
reply.
## CURLFTPSSL_CCC_ACTIVE
Initiate the shutdown and wait for a reply.
# DEFAULT
CURLFTPSSL_CCC_NONE
# %PROTOCOLS%
# EXAMPLE
~~~c
int main(void)
{
CURL *curl = curl_easy_init();
if(curl) {
CURLcode res;
curl_easy_setopt(curl, CURLOPT_URL, "ftp://example.com/file.txt");
curl_easy_setopt(curl, CURLOPT_USE_SSL, CURLUSESSL_CONTROL);
/* go back to clear-text FTP after authenticating */
curl_easy_setopt(curl, CURLOPT_FTP_SSL_CCC, CURLFTPSSL_CCC_ACTIVE);
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
}
~~~
# HISTORY
**CURLFTPSSL_*** enums became `long` types in 8.16.0, prior to this version
a `long` cast was necessary when passed to curl_easy_setopt(3).
# %AVAILABILITY%
# 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, see
libcurl-errors(3).