How to read a function definition (prototype)Podręcznik PHPPoprzedniDodatek K. About the manualNastępnyHow to read a function definition (prototype)
Each function is documented for quick reference, knowing how
to read and understand the manual will make using PHP
much easier. Rather than relying on examples or cut/paste, you want
to know how to read function definitions (prototypes). Let's begin:
Prerequisite: Basic understanding of types:
Although PHP is a loosly typed language, it's important to have
a basic understanding of types as
they have important meaning.
Function definitions tell us what
type of value is returned,
let's use the definition for strlen() as our first example:
strlen
(PHP 3, PHP 4 >= 4.0.0)
strlen -- Get string length
Description
int strlen ( string str )
Returns the length of string.
Tabela K-1. Explanation of a function definitionPartDescription
strlen
The function name.
(PHP 3, PHP 4 >= 4.0.0)
strlen() has been around in both all of PHP 3 and PHP 4
int
Type of value this function returns, which is an
integer
(i.e. The length of a string is measured in numbers).
( string str )
The first (and in this case the only) parameter/argument for the
function strlen() is named str, and it's a
string.
We could rewrite the above function definition in a generic way:
returned type function name ( parameter type parameter name )
Many functions take on multiple parameters, such as in_array().
It's prototype is as follows:
bool in_array ( mixed needle, array haystack [, bool strict])
What does this mean? in_array() returns a
boolean value, TRUE on
success (the needle was found in the
haystack) or FALSE on failure (the
needle was not found in the
haystack). The first parameter is named
needle and it can be many different
types, so we call it
"mixed". This mixed needle
(what we're looking for) can either be a scalar value (string, integer,
or float), or an
array.
haystack (the array we're searching in) is the
second parameter. The third optional parameter is
named strict. All optional parameters are seen
in [ brackets ]. The manual
states that the strict parameter defaults to
boolean FALSE. See the manual page on each function for details on
how they work.
PoprzedniSpis treściNastępnyAbout user notesPoczątek rozdziałuPHP versions documented in this manual
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