curl-curl/docs/libcurl/opts/CURLOPT_PORT.md
Daniel Stenberg b4dba346cd
stop using the word 'just'
Everywhere. In documentation and code comments.

It is almost never a good word and almost always a filler that should be
avoided.

Closes #20793
2026-03-03 15:30:22 +01:00

1.6 KiB

c SPDX-License-Identifier Title Section Source See-also Protocol Added-in
Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. curl CURLOPT_PORT 3 libcurl
CURLINFO_PRIMARY_PORT (3)
CURLOPT_STDERR (3)
CURLOPT_URL (3)
All
7.1

NAME

CURLOPT_PORT - remote port number to connect to

SYNOPSIS

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PORT, long number);

DESCRIPTION

We discourage using this option since its scope is not obvious and hard to predict. Set the preferred port number in the URL instead.

This option sets number to be the remote port number to connect to, instead of the one specified in the URL or the default port for the used protocol.

Usually, you let the URL decide which port to use but this allows the application to override that.

While this option accepts a 'long', a port number is an unsigned 16-bit number and therefore using a port number lower than zero or over 65535 causes a CURLE_BAD_FUNCTION_ARGUMENT error.

DEFAULT

0 which makes it not used. This also makes port number zero impossible to set with this API.

%PROTOCOLS%

EXAMPLE

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/foo.bin");
    curl_easy_setopt(curl, CURLOPT_PORT, 8080L);
    result = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}

%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).