Language Reference

Table of Contents

• Basic syntax
  • PHP tags
  • Escaping from HTML
  • Instruction separation
  • Comments
• Types
  • Introduction
  • Type System
  • NULL
  • Booleans
  • Integers
  • Floating point numbers
  • Strings
  • Numeric strings
  • Arrays
  • Objects
  • Enumerations
  • Resources
  • Callbacks / Callables
  • Mixed
  • Void
  • Never
  • Relative class types
  • Value types
  • Iterables
  • Type declarations
  • Type Juggling
• Variables
  • Basics
  • Predefined Variables
  • Variable scope
  • Variable variables
  • Variables From External Sources
• Constants
  • Syntax
  • Predefined constants
  • Magic constants
• Expressions
• Operators
  • Operator Precedence — Operator Precedence
  • Arithmetic — Arithmetic Operators
  • Increment and Decrement — Incrementing/Decrementing Operators
  • Assignment — Assignment Operators
  • Bitwise — Bitwise Operators
  • Comparison — Comparison Operators
  • Error Control — Error Control Operators
  • Execution — Execution Operators
  • Logic — Logical Operators
  • String — String Operators
  • Array — Array Operators
  • Type — Type Operators
• Control Structures
  • Introduction
  • if
  • else
  • elseif/else if
  • Alternative syntax for control structures
  • while
  • do-while
  • for
  • foreach
  • break
  • continue
  • switch
  • match
  • declare
  • return
  • require
  • include
  • require_once
  • include_once
  • goto
• Functions
  • User-defined functions
  • Function arguments
  • Returning values
  • Variable functions
  • Internal (built-in) functions
  • Anonymous functions
  • Arrow Functions
  • First class callable syntax
• Classes and Objects
  • Introduction
  • The Basics
  • Properties
  • Class Constants
  • Autoloading Classes
  • Constructors and Destructors
  • Visibility
  • Object Inheritance
  • Scope Resolution Operator (::)
  • Static Keyword
  • Class Abstraction
  • Object Interfaces
  • Traits
  • Anonymous classes
  • Overloading
  • Object Iteration
  • Magic Methods
  • Final Keyword
  • Object Cloning
  • Comparing Objects
  • Late Static Bindings
  • Objects and references
  • Object Serialization — Serializing objects - objects in sessions
  • Covariance and Contravariance
  • Lazy Objects
  • OOP Changelog
• Namespaces
  • Overview — Namespaces overview
  • Namespaces — Defining namespaces
  • Sub-namespaces — Declaring sub-namespaces
  • Defining multiple namespaces in the same file — Defining multiple namespaces in the same file
  • Basics — Using namespaces: Basics
  • Namespaces and dynamic language features — Namespaces and dynamic language features
  • namespace keyword and __NAMESPACE__ — The namespace keyword and __NAMESPACE__ magic constant
  • Aliasing and Importing — Using namespaces: Aliasing/Importing
  • Global space — Global space
  • Fallback to global space — Using namespaces: fallback to the global space for functions and constants
  • Name resolution rules — Name resolution rules
  • FAQ — FAQ: things you need to know about namespaces
• Enumerations
  • Enumerations overview
  • Basic enumerations
  • Backed enumerations
  • Enumeration methods
  • Enumeration static methods
  • Enumeration constants
  • Traits
  • Enum values in constant expressions
  • Differences from objects
  • Value listing
  • Serialization
  • Why enums aren't extendable
  • Examples
• Errors
  • Introduction
  • Basics
  • Errors in PHP 7
• Exceptions
  • catch
  • finally
  • Global exception handler
  • Notes
  • Examples
  • Extending Exceptions
• Fibers
• Generators
  • Generators overview
  • Generator syntax
  • Comparing generators with Iterator objects
• Attributes
  • Attributes overview
  • Attribute syntax
  • Reading Attributes with the Reflection API
  • Declaring Attribute Classes
• References Explained
  • What References Are
  • What References Do
  • What References Are Not
  • Passing by Reference
  • Returning References
  • Unsetting References
  • Spotting References
• Predefined Variables
  • Superglobals — Built-in variables that are always available in all scopes
  • $GLOBALS — References all variables available in global scope
  • $_SERVER — Server and execution environment information
  • $_GET — HTTP GET variables
  • $_POST — HTTP POST variables
  • $_FILES — HTTP File Upload variables
  • $_REQUEST — HTTP Request variables
  • $_SESSION — Session variables
  • $_ENV — Environment variables
  • $_COOKIE — HTTP Cookies
  • $php_errormsg — The previous error message
  • $http_response_header — HTTP response headers
  • $argc — The number of arguments passed to script
  • $argv — Array of arguments passed to script
• Predefined Exceptions
  • Exception — Exception
  • ErrorException — ErrorException
  • ClosedGeneratorException — The ClosedGeneratorException class
  • Error — Error
  • ArgumentCountError — ArgumentCountError
  • ArithmeticError — ArithmeticError
  • AssertionError — AssertionError
  • DivisionByZeroError — DivisionByZeroError
  • CompileError — CompileError
  • ParseError — ParseError
  • TypeError — TypeError
  • ValueError — ValueError
  • UnhandledMatchError — UnhandledMatchError
  • FiberError — FiberError
• Predefined Interfaces and Classes
  • Traversable — The Traversable interface
  • Iterator — The Iterator interface
  • IteratorAggregate — The IteratorAggregate interface
  • InternalIterator — The InternalIterator class
  • Throwable — Throwable
  • ArrayAccess — The ArrayAccess interface
  • Serializable — The Serializable interface
  • Closure — The Closure class
  • stdClass — The stdClass class
  • Generator — The Generator class
  • Fiber — The Fiber class
  • WeakReference — The WeakReference class
  • WeakMap — The WeakMap class
  • Stringable — The Stringable interface
  • UnitEnum — The UnitEnum interface
  • BackedEnum — The BackedEnum interface
  • SensitiveParameterValue — The SensitiveParameterValue class
  • __PHP_Incomplete_Class — The __PHP_Incomplete_Class class
• Predefined Attributes
  • Attribute — The Attribute attribute
  • AllowDynamicProperties — The AllowDynamicProperties attribute
  • Deprecated — The Deprecated attribute
  • Override — The Override attribute
  • ReturnTypeWillChange — The ReturnTypeWillChange attribute
  • SensitiveParameter — The SensitiveParameter attribute
• Context options and parameters
  • Socket context options — Socket context option listing
  • HTTP context options — HTTP context option listing
  • FTP context options — FTP context option listing
  • SSL context options — SSL context option listing
  • Phar context options — Phar context option listing
  • Context parameters — Context parameter listing
  • Zip context options — Zip context option listing
  • Zlib context options — Zlib context option listing
• Supported Protocols and Wrappers
  • file:// — Accessing local filesystem
  • http:// — Accessing HTTP(s) URLs
  • ftp:// — Accessing FTP(s) URLs
  • php:// — Accessing various I/O streams
  • zlib:// — Compression Streams
  • data:// — Data (RFC 2397)
  • glob:// — Find pathnames matching pattern
  • phar:// — PHP Archive
  • ssh2:// — Secure Shell 2
  • rar:// — RAR
  • ogg:// — Audio streams
  • expect:// — Process Interaction Streams