Php+apache implementing an If statement alarm

Php+apache executing an IF statement alarm
if (Strstr ($a, "add"))//If the "add" character exists in the string
{
$bb. = $k. " ". $a; $b fetch $ A
}
if (Strstr ($a, "return") | | STRSTR ("Data"))//If there is a "return" or "data" character in the string ******apache the Error.log has been prompted here to error
{
Break
}
ElseIf (!STRSTR ($a, "return"))//If there is no "return" in the string
{
Executes the following statement.
The warning prompts are as follows:
DEC 20:42:33 [ERROR] [client 127.0.0.1] PHP Warning:strstr () expects at least 2 parameters, 1 given in c:\\progr Am files\\www\\fail\\collectdata.php on line 33
is not my judgment statement wrong .... Seemingly can also be carried out, but the alarm prompts constantly, close php.ini Error_report also can not avoid the Apache Error.log constantly increase, is a headache, I rookie, wait for the great god Enlighten.


------Solution--------------------
if (Strstr ($a, "return")
------Solution--------------------
Strstr ( $a"data"))

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