1--TEST-- 2header() and friends 3--FILE-- 4<?php 5 6$v1 = headers_sent(); 7$v2 = headers_list(); 8var_dump(header("HTTP 1.0", true, 200)); 9 10var_dump($v1); 11var_dump($v2); 12 13var_dump(header("")); 14var_dump(header("", true)); 15var_dump(headers_sent()); 16var_dump(headers_list()); 17var_dump(header("HTTP blah")); 18var_dump(header("HTTP blah", true)); 19var_dump(headers_sent()); 20var_dump(headers_list()); 21 22echo "Done\n"; 23?> 24--EXPECTF-- 25NULL 26bool(false) 27array(0) { 28} 29 30Warning: Cannot modify header information - headers already sent by (output started at %s:%d) in %s on line %d 31NULL 32 33Warning: Cannot modify header information - headers already sent by (output started at %s:%d) in %s on line %d 34NULL 35bool(true) 36array(0) { 37} 38 39Warning: Cannot modify header information - headers already sent by (output started at %s:%d) in %s on line %d 40NULL 41 42Warning: Cannot modify header information - headers already sent by (output started at %s:%d) in %s on line %d 43NULL 44bool(true) 45array(0) { 46} 47Done 48