Difference between 1 and true - php

Question

I am trying to use this PHP script to get the shortened link from bit.ly API.. It works fine but my question is there any way to make this script more efficient or take some unnecessary parts out of it. Also my main question is that when I use:
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
I have to use the trim function on $data but when I use:
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
I don't have to do that.. Why is it causing a line break after the link when I use 1 instead of true?
<?php
function get_bitly_short_url($url, $format = 'txt')
{
$connectURL = 'http://api.j.mp/v3/shorten?login=(MY USERNAME)&apiKey=(MY API)&uri=' . urlencode($url) . '&format=' . $format;
return curl_get_result($connectURL);
}
function curl_get_result($url)
{
$ch = curl_init();
$timeout = 5;
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
$data = curl_exec($ch);
curl_close($ch);
return trim($data);
}
$short_url = get_bitly_short_url('http://google.com');
?>

Answer 1

1 !== true in common case, but in your case, should be no difference,
double check all other things...
I make simple test for you:
<?php
$url = 'http://ziptasticapi.com/92530';
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 5);
$data = curl_exec($ch);
curl_close($ch);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 5);
$data1 = curl_exec($ch);
curl_close($ch);
var_dump($data);
echo "\n";
var_dump($data1);
Results:
string(52) "{"country":"US","state":"CA","city":"LAKE ELSINORE"}"
string(52) "{"country":"US","state":"CA","city":"LAKE ELSINORE"}"
So, bugs in php happens, but no bugs this time
No difference, check other parts of your system
Luck!