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 (int)

The current PHP "major" version as an integer (e.g., int(5) from version "5.2.7-extra").

PHP_MINOR_VERSION (int)

The current PHP "minor" version as an integer (e.g., int(2) from version "5.2.7-extra").

PHP_RELEASE_VERSION (int)

The current PHP "release" version as an integer (e.g., int(7) from version "5.2.7-extra").

PHP_VERSION_ID (int)

The current PHP version as an integer, useful for version comparisons (e.g., int(50207) from version "5.2.7-extra").

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.

PHP_ZTS (int)

PHP_DEBUG (int)

PHP_MAXPATHLEN (int)

The maximum length of filenames (including path) supported by this build of PHP.

PHP_OS (string)

The operating system PHP was built for.

PHP_OS_FAMILY (string)

The operating system family PHP was built for. One of 'Windows', 'BSD', 'Darwin', 'Solaris', 'Linux' or 'Unknown'. Available as of PHP 7.2.0.

PHP_SAPI (string)

The Server API for this build of PHP. See also php_sapi_name().

PHP_EOL (string)

The correct 'End Of Line' symbol for this platform.

PHP_INT_MAX (int)

The largest integer supported in this build of PHP. Usually int(2147483647) in 32 bit systems and int(9223372036854775807) in 64 bit systems.

PHP_INT_MIN (int)

The smallest integer supported in this build of PHP. Usually int(-2147483648) in 32 bit systems and int(-9223372036854775808) in 64 bit systems. Usually, PHP_INT_MIN === ~PHP_INT_MAX.

PHP_INT_SIZE (int)

The size of an integer in bytes in this build of PHP.

PHP_FLOAT_DIG (int)

Number of decimal digits that can be rounded into a float and back without precision loss. Available as of PHP 7.2.0.

PHP_FLOAT_EPSILON (float)

Smallest representable positive number x, so that x + 1.0 != 1.0. Available as of PHP 7.2.0.

PHP_FLOAT_MIN (float)

Smallest representable positive floating point number. If you need the smallest representable negative floating point number, use - PHP_FLOAT_MAX. Available as of PHP 7.2.0.

PHP_FLOAT_MAX (float)

Largest representable floating point number. Available as of PHP 7.2.0.

DEFAULT_INCLUDE_PATH (string)

PEAR_INSTALL_DIR (string)

PEAR_EXTENSION_DIR (string)

PHP_EXTENSION_DIR (string)

The default directory where to look for dynamically loadable extensions (unless overridden by extension_dir). Defaults to PHP_PREFIX (or PHP_PREFIX . "\\ext" on Windows).

PHP_PREFIX (string)

The value --prefix was set to at configure. On Windows, it is the value --with-prefix was set to at configure.

PHP_BINDIR (string)

The value --bindir was set to at configure. On Windows, it is the value --with-prefix was set to at configure.

PHP_BINARY (string)

Specifies the PHP binary path during script execution.

PHP_MANDIR (string)

Specifies where the manpages were installed into.

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).

PHP_FD_SETSIZE (string)

The maximum number of file descriptors for select system calls. Available as of PHP 7.1.0.

E_ERROR (int)

Error reporting constant

E_WARNING (int)

Error reporting constant

E_PARSE (int)

Error reporting constant

E_NOTICE (int)

Error reporting constant

E_CORE_ERROR (int)

Error reporting constant

E_CORE_WARNING (int)

Error reporting constant

E_COMPILE_ERROR (int)

Error reporting constant

E_COMPILE_WARNING (int)

Error reporting constant

E_USER_ERROR (int)

Error reporting constant

E_USER_WARNING (int)

Error reporting constant

E_USER_NOTICE (int)

Error reporting constant

E_RECOVERABLE_ERROR (int)

Error reporting constant.

E_DEPRECATED (int)

Error reporting constant.

E_USER_DEPRECATED (int)

Error reporting constant.

E_ALL (int)

Error reporting constant

E_STRICT (int)

Error reporting constant

__COMPILER_HALT_OFFSET__ (int)

true (bool)

See Booleans.

false (bool)

See Booleans.

null (null)

See Null.

PHP_WINDOWS_EVENT_CTRL_C (int)

A Windows CTRL+C event. Available as of PHP 7.4.0 (Windows only).

PHP_WINDOWS_EVENT_CTRL_BREAK (int)

A Windows CTRL+BREAK event. Available as of PHP 7.4.0 (Windows only).

See also: Magic constants.

Standard Predefined Constants

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