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.

ZEND_THREAD_SAFE (bool)

Indicates whether the current build of PHP is thread safe.

ZEND_DEBUG_BUILD (bool)

Indicates whether the current build of PHP is a debug build.

PHP_ZTS (bool) Alias of ZEND_THREAD_SAFE

Indicates whether the current build of PHP is thread safe.

PHP_DEBUG (bool) Alias of ZEND_DEBUG_BUILD

Indicates whether the current build of PHP is a debug build.

DEBUG_BACKTRACE_PROVIDE_OBJECT (int)

Populate the "object" index.

DEBUG_BACKTRACE_IGNORE_ARGS (int)

Don't include the argument information for functions in the stack trace.

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 (