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Predefined Constants
List of Reserved Words
PHP Manual

Predefined Constants

Core Predefined Constants

These constants are defined by the PHP core. This includes PHP, the Zend engine, and SAPI modules.

PHP_VERSION (string)
The current PHP version as a string in "major.minor.release[extra]" notation.
PHP_MAJOR_VERSION (integer)
The current PHP "major" version as an integer (e.g., int(5) from version "5.2.7-extra"). Available since PHP 5.2.7.
PHP_MINOR_VERSION (integer)
The current PHP "minor" version as an integer (e.g., int(2) from version "5.2.7-extra"). Available since PHP 5.2.7.
PHP_RELEASE_VERSION (integer)
The current PHP "release" version as an integer (e.g., int(7) from version "5.2.7-extra"). Available since PHP 5.2.7.
PHP_VERSION_ID (integer)
The current PHP version as an integer, useful for version comparisons (e.g., int(50207) from version "5.2.7-extra"). Available since PHP 5.2.7.
PHP_EXTRA_VERSION (string)
The current PHP "extra" version as a string (e.g., '-extra' from version "5.2.7-extra"). Often used by distribution vendors to indicate a package version. Available since PHP 5.2.7.
PHP_ZTS (integer)
Available since PHP 5.2.7.
PHP_DEBUG (integer)
Available since PHP 5.2.7.
PHP_MAXPATHLEN (integer)
The maximum length of filenames (including path) supported by this build of PHP. Available since PHP 5.3.0.
PHP_OS (string)
PHP_SAPI (string)
The Server API for this build of PHP. Available since PHP 4.2.0. See also php_sapi_name().
PHP_EOL (string)
The correct 'End Of Line' symbol for this platform. Available since PHP 4.3.10 and PHP 5.0.2
PHP_INT_MAX (integer)
The largest integer supported in this build of PHP. Usually int(2147483647). Available since PHP 4.4.0 and PHP 5.0.5
PHP_INT_SIZE (integer)
Available since PHP 4.4.0 and PHP 5.0.5
DEFAULT_INCLUDE_PATH (string)
PEAR_INSTALL_DIR (string)
PEAR_EXTENSION_DIR (string)
PHP_EXTENSION_DIR (string)
PHP_PREFIX (string)
The value "--prefix" was set to at configure. Available since PHP 4.3.0.
PHP_BINDIR (string)
Specifies where the binaries were installed into.
PHP_BINARY (string)
Specifies the PHP binary path during script execution. Available since PHP 5.4.
PHP_MANDIR (string)
Specifies where the manpages were installed into. Available since PHP 5.3.7.
PHP_LIBDIR (string)
PHP_DATADIR (string)
PHP_SYSCONFDIR (string)
PHP_LOCALSTATEDIR (string)
PHP_CONFIG_FILE_PATH (string)
PHP_CONFIG_FILE_SCAN_DIR (string)
PHP_SHLIB_SUFFIX (string)
The build-platform's shared library suffix, such as "so" (most Unixes) or "dll" (Windows). Available since PHP 4.3.0
E_ERROR (integer)
Error reporting constant
E_WARNING (integer)
E_PARSE (integer)
E_NOTICE (integer)
E_CORE_ERROR (integer)
E_CORE_WARNING (integer)
E_COMPILE_ERROR (integer)
E_COMPILE_WARNING (integer)
E_USER_ERROR (integer)
E_USER_WARNING (integer)
E_USER_NOTICE (integer)
E_DEPRECATED (integer)
Available since PHP 5.3.0
E_USER_DEPRECATED (integer)
Available since PHP 5.3.0
E_ALL (integer)
E_STRICT (integer)
Available since PHP 5.0.0
__COMPILER_HALT_OFFSET__ (integer)
Available since PHP 5.1.0
TRUE (boolean)
See Booleans.
FALSE (boolean)
See Booleans.
NULL (boolean)
See Null.

See also: Magic constants.

Standard Predefined Constants

All constants from core extensions are defined in PHP by default.


List of Reserved Words
PHP Manual