Tribblix: manual page: CURLOPT

CURLOPT_FTPPORT(3) Introduction to Library Functions CURLOPT_FTPPORT(3)

NAME

CURLOPT_FTPPORT - make FTP transfer active

SYNOPSIS

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_FTPPORT, char *spec);

DESCRIPTION

Pass a pointer to a null-terminated string as parameter. It specifies
that the FTP transfer should be made actively and the given string is
used to get the IP address to use for the FTP PORT instruction.

The PORT instruction tells the remote server to do a TCP connect to
our specified IP address. The string may be a plain IP address, a
hostname, a network interface name (under Unix) or just a '-' symbol
to let the library use your system's default IP address. Default FTP
operations are passive, and does not use the PORT command.

The address can be followed by a ':' to specify a port, optionally
followed by a '-' to specify a port range. If the port specified is
0, the operating system picks a free port. If a range is provided and
all ports in the range are not available, libcurl reports
CURLE_FTP_PORT_FAILED for the handle. Invalid port/range settings are
ignored. IPv6 addresses followed by a port or port range have to be
in brackets. IPv6 addresses without port/range specifier can be in
brackets.

Examples with specified ports:

eth0:0
192.168.1.2:32000-33000
curl.se:32123
[::1]:1234-4567

We strongly advise against specifying the address with a name, as it
causes libcurl to do a blocking name resolve call to retrieve the IP
address. That name resolve operation does not use DNS-over-HTTPS even
if CURLOPT_DOH_URL(3) is set.

Using anything else than "-" for this option should typically only be
done if you have special knowledge and confirmation that it works.

The application does not have to keep the string around after setting
this option.

Using this option multiple times makes the last set string override
the previous ones. You disable PORT again and go back to using the
passive version by setting this option to NULL.

DEFAULT

NULL

PROTOCOLS

This functionality affects ftp only

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");
curl_easy_setopt(curl, CURLOPT_FTPPORT, "-");
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
}

AVAILABILITY

Added in curl 7.1

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).