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Defining multiple namespaces in the same file

Defining multiple namespaces in the same file

(PHP 5 >= 5.3.0, PHP 7)

Multiple namespaces may also be declared in the same file. There are two allowed syntaxes.

Example #1 Declaring multiple namespaces, simple combination syntax

<?php namespace MyProject; const CONNECT_OK = 1; class Connection { /* ... */ } function connect() { /* ... */  } namespace AnotherProject; const CONNECT_OK = 1; class Connection { /* ... */ } function connect() { /* ... */  } ?>

This syntax is not recommended for combining namespaces into a single file. Instead it is recommended to use the alternate bracketed syntax.

Example #2 Declaring multiple namespaces, bracketed syntax

<?php namespace MyProject { const CONNECT_OK = 1; class Connection { /* ... */ } function connect() { /* ... */  } } namespace AnotherProject { const CONNECT_OK = 1; class Connection { /* ... */ } function connect() { /* ... */  } } ?>

It is strongly discouraged as a coding practice to combine multiple namespaces into the same file. The primary use case is to combine multiple PHP scripts into the same file.

To combine global non-namespaced code with namespaced code, only bracketed syntax is supported. Global code should be encased in a namespace statement with no namespace name as in:

Example #3 Declaring multiple namespaces and unnamespaced code

<?php namespace MyProject { const CONNECT_OK = 1; class Connection { /* ... */ } function connect() { /* ... */  } } namespace { // global code session_start( $a = MyProject\connect( echo MyProject\Connection::start( } ?>

No PHP code may exist outside of the namespace brackets except for an opening declare statement.

Example #4 Declaring multiple namespaces and unnamespaced code

<?php declare(encoding='UTF-8' namespace MyProject { const CONNECT_OK = 1; class Connection { /* ... */ } function connect() { /* ... */  } } namespace { // global code session_start( $a = MyProject\connect( echo MyProject\Connection::start( } ?>

← Declaring sub-namespaces

Using namespaces: Basics →

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