[GameWizard]

Thanks for your reply, I think I may have stumbled upon what I need, but am having no luck with the result.

Inside includes/functions.php I discovered the following lines:

Line 1226:

define('FETCH_USERINFO_ISFRIEND',   0x80);

Line 1269:

    // no cache available - query the user
    $user = $vbulletin->db->query_first_slave("
        SELECT " .
            iif(($option & FETCH_USERINFO_ADMIN), ' administrator.*, ') . "
            userfield.*, usertextfield.*, user.*, UNIX_TIMESTAMP(passworddate) AS passworddate,
            IF(displaygroupid=0, user.usergroupid, displaygroupid) AS displaygroupid" .
            iif(($option & FETCH_USERINFO_AVATAR) AND $vbulletin->options['avatarenabled'], ', avatar.avatarpath, NOT ISNULL(customavatar.userid) AS hascustomavatar, customavatar.dateline AS avatardateline, customavatar.width AS avwidth, customavatar.height AS avheight, customavatar.height_thumb AS avheight_thumb, customavatar.width_thumb AS avwidth_thumb, customavatar.filedata_thumb').
            iif(($option & FETCH_USERINFO_PROFILEPIC), ', customprofilepic.userid AS profilepic, customprofilepic.dateline AS profilepicdateline, customprofilepic.width AS ppwidth, customprofilepic.height AS ppheight') .
            iif(($option & FETCH_USERINFO_SIGPIC), ', sigpic.userid AS sigpic, sigpic.dateline AS sigpicdateline, sigpic.width AS sigpicwidth, sigpic.height AS sigpicheight') .
            (($option & FETCH_USERINFO_USERCSS) ? ', usercsscache.cachedcss, IF(usercsscache.cachedcss IS NULL, 0, 1) AS hascachedcss, usercsscache.buildpermissions AS cssbuildpermissions' : '') .
            iif(!isset($vbphrase), fetch_language_fields_sql(), '') .
            (($vbulletin->userinfo['userid'] AND ($option & FETCH_USERINFO_ISFRIEND)) ?
                ", IF(userlist1.friend = 'yes', 1, 0) AS isfriend, IF (userlist1.friend = 'pending' OR userlist1.friend = 'denied', 1, 0) AS ispendingfriend" .
                ", IF(userlist1.userid IS NOT NULL, 1, 0) AS u_iscontact_of_bbuser, IF (userlist2.friend = 'pending', 1, 0) AS requestedfriend" .
                ", IF(userlist2.userid IS NOT NULL, 1, 0) AS bbuser_iscontact_of_user" : "") . "
            $hook_query_fields
        FROM " . TABLE_PREFIX . "user AS user
        LEFT JOIN " . TABLE_PREFIX . "userfield AS userfield ON (user.userid = userfield.userid)
        LEFT JOIN " . TABLE_PREFIX . "usertextfield AS usertextfield ON (usertextfield.userid = user.userid) " .
        iif(($option & FETCH_USERINFO_AVATAR) AND $vbulletin->options['avatarenabled'], "LEFT JOIN " . TABLE_PREFIX . "avatar AS avatar ON (avatar.avatarid = user.avatarid) LEFT JOIN " . TABLE_PREFIX . "customavatar AS customavatar ON (customavatar.userid = user.userid) ") .
        iif(($option & FETCH_USERINFO_PROFILEPIC), "LEFT JOIN " . TABLE_PREFIX . "customprofilepic AS customprofilepic ON (user.userid = customprofilepic.userid) ") .
        iif(($option & FETCH_USERINFO_ADMIN), "LEFT JOIN " . TABLE_PREFIX . "administrator AS administrator ON (administrator.userid = user.userid) ") .
        iif(($option & FETCH_USERINFO_SIGPIC), "LEFT JOIN " . TABLE_PREFIX . "sigpic AS sigpic ON (user.userid = sigpic.userid) ") .
        (($option & FETCH_USERINFO_USERCSS) ? 'LEFT JOIN ' . TABLE_PREFIX . 'usercsscache AS usercsscache ON (user.userid = usercsscache.userid)' : '') .
        iif(!isset($vbphrase), "LEFT JOIN " . TABLE_PREFIX . "language AS language ON (language.languageid = " . (!empty($languageid) ? $languageid : "IF(user.languageid = 0, " . intval($vbulletin->options['languageid']) . ", user.languageid)") . ") ") .
        (($vbulletin->userinfo['userid'] AND ($option & FETCH_USERINFO_ISFRIEND)) ?
            "LEFT JOIN " . TABLE_PREFIX . "userlist AS userlist1 ON (userlist1.relationid = user.userid AND userlist1.type = 'buddy' AND userlist1.userid = " . $vbulletin->userinfo['userid'] . ")" .
            "LEFT JOIN " . TABLE_PREFIX . "userlist AS userlist2 ON (userlist2.userid = user.userid AND userlist2.type = 'buddy' AND userlist2.relationid = " . $vbulletin->userinfo['userid'] . ")" : "") . "
        $hook_query_joins
        WHERE user.userid = $userid
    ");

The code in red seems to be defining what it is that the isfriend function is suposed to do, am I correct? I tried different ways of creating a plugin based on this code and merging it into yours in different ways but came up with errors. It seems that what i need to do is re-fetch this command, rather than copying and pasting it over again.

Can anyone help me with this?