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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.

PHP Manual