Zend Certification PHP 5 : Difference between isset() and other is_*() functions

[oggy]

Hello
I try to answer this question for the Zend Certification PHP 5 :
"What is the difference between isset() and other is_*() functions
(is_alpha(), is_number(), etc.)?"

Do you have a solution ?

Thanks

[ZeldorBlat]

Re: Zend Certification PHP 5 : Difference between isset() and other is_*() functions


oggy wrote:

Hello
I try to answer this question for the Zend Certification PHP 5 :
"What is the difference between isset() and other is_*() functions
(is_alpha(), is_number(), etc.)?"
>
Do you have a solution ?
>
Thanks

Read this:
<http://www.php.net/isset>

In particular the warning that "isset() only works with variables as
passing anything else will result in a parse error" and the note that
"Because this is a language construct and not a function, it cannot be
called using variable functions."

[oggy]

Re: Zend Certification PHP 5 : Difference between isset() and other is_*() functions

thanks a lot
"isset() only works with variables" means that its not working with
constants (only).

On 27 déc, 20:21, "ZeldorBlat " <zeldorb...@gma il.comwrote:

oggy wrote:

Hello
I try to answer this question for the Zend Certification PHP 5 :
"What is the difference between isset() and other is_*() functions
(is_alpha(), is_number(), etc.)?"

>

Do you have a solution ?

>

ThanksRead this:

<http://www.php.net/isset>
>
In particular the warning that "isset() only works with variables as
passing anything else will result in a parse error" and the note that
"Because this is a language construct and not a function, it cannot be
called using variable functions."

[ZeldorBlat]

Re: Zend Certification PHP 5 : Difference between isset() and other is_*() functions


oggy wrote:

thanks a lot
"isset() only works with variables" means that its not working with
constants (only).
>

That's half of it. The other half is that it won't work with the
return value of a function call (directly). Consider the following:

function foo() {
return 1;
}

//This is ok:
$x = foo();
isset($x);

//But this throws a fatal error:
isset(foo());