php - Variable only available after echo -

i perplexed @ experiencing tonight. have spent hour trying debug have gone nowhere. hope overlooking simple....

the problem getting id , storing variable ($event), starting our session , loading $event session array. happening if not echo text browser window, variable doesn't set in session. if echo browser, variable referenced correctly. have done var_dump on $event , correctly being stored string of length x x length of id.

here relevant code:

$event = $this->event_model->get_event_id_with_form_id($batch->event_id); // call returns "100" session_start(); $_session['ckfinder'] = array (); $_session['ckfinder']['enabled'] = true; $_session['ckfinder']['uploadurl'] = '/assets/event_uploads/' . $event . '/';  echo $_session['ckfinder']['uploadurl']; // returns "/assets/event_uploads//" 

however, var_dump($event) returns string(3) "100" know $event exists.

weirder still if explicitly set $event '100', echo call returns "/assets/event_uploads/100/".

and weirder still if keep above code (with call $this->event_model), add echo after session_start (ie echo 'a';), again echo call return correct path.

it not clear me why happening. have never experienced issue php, though again, may being caused lack of sleep.

try call

session_write_close() 

after set variables.