(PECL OAuth >= 0.99.1)
OAuth::getAccessToken — Fetch an access token
$access_token_url
   [, string $auth_session_handle
   [, string $verifier_token
   [, string $http_method
  ]]] )Fetch an access token, secret and any additional response parameters from the service provider.
access_token_urlURL to the access token API.
auth_session_handleAuthorization session handle, this parameter does not have any citation in the core OAuth 1.0 specification but may be implemented by large providers. » See ScalableOAuth for more information.
verifier_token
       For service providers which support 1.0a, a verifier_token
       must be passed while exchanging the request token for the access
       token. If the verifier_token is present in $_GET 
       or $_POST it is passed automatically and the caller 
       does not need to specify a verifier_token (usually if the access token 
       is exchanged at the oauth_callback URL).
       » See ScalableOAuth
       for more information.
      
http_methodHTTP method to use, e.g. GET or POST.
   Returns an array containing the parsed OAuth response on success or FALSE on failure.
  
| Version | Description | 
|---|---|
| 1.0.0 | Previously returned NULLon failure, instead ofFALSE. | 
| 0.99.9 | The verifier_tokenparameter was added | 
Example #1 OAuth::getAccessToken() example
<?php
try {
    $oauth = new OAuth(OAUTH_CONSUMER_KEY,OAUTH_CONSUMER_SECRET);
    $oauth->setToken($request_token,$request_token_secret);
    $access_token_info = $oauth->getAccessToken("https://example.com/oauth/access_token");
    if(!empty($access_token_info)) {
        print_r($access_token_info);
    } else {
        print "Failed fetching access token, response was: " . $oauth->getLastResponse();
    }
} catch(OAuthException $E) {
    echo "Response: ". $E->lastResponse . "\n";
}
?>
The above example will output something similar to:
Array
(
    [oauth_token] => some_token
    [oauth_token_secret] => some_token_secret
)