## 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)
`PHP_OS` (string)
`PHP_SAPI` (string)
  Available since PHP 4.2.0. See also php_sapi_name().
`PHP_EOL` (string)
  Available since PHP 4.3.10 and PHP 5.0.2
`PHP_INT_MAX` (integer)
  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)
  Available since PHP 4.3.0
`PHP_BINDIR` (string)
`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)
  Available since PHP 4.3.0
`PHP_OUTPUT_HANDLER_START` (integer)
`PHP_OUTPUT_HANDLER_CONT` (integer)
`PHP_OUTPUT_HANDLER_END` (integer)
`E_ERROR` (integer)
`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_ALL` (integer)
`E_STRICT` (integer)
  Available since PHP 5.0.0
`__COMPILER_HALT_OFFSET__` (integer)
  Available since PHP 5.1.0

See also: Magic constants.

### Standard Predefined Constants

These constants are defined in PHP by default.

`EXTR_OVERWRITE` (integer)
`EXTR_SKIP` (integer)
`EXTR_PREFIX_SAME` (integer)
`EXTR_PREFIX_ALL` (integer)
`EXTR_PREFIX_INVALID` (integer)
`EXTR_PREFIX_IF_EXISTS` (integer)
`EXTR_IF_EXISTS` (integer)
`SORT_ASC` (integer)
`SORT_DESC` (integer)
`SORT_REGULAR` (integer)
`SORT_NUMERIC` (integer)
`SORT_STRING` (integer)
`CASE_LOWER` (integer)
`CASE_UPPER` (integer)
`COUNT_NORMAL` (integer)
`COUNT_RECURSIVE` (integer)
`ASSERT_ACTIVE` (integer)
`ASSERT_CALLBACK` (integer)
`ASSERT_BAIL` (integer)
`ASSERT_WARNING` (integer)
`ASSERT_QUIET_EVAL` (integer)
`CONNECTION_ABORTED` (integer)
`CONNECTION_NORMAL` (integer)
`CONNECTION_TIMEOUT` (integer)
`INI_USER` (integer)
`INI_PERDIR` (integer)
`INI_SYSTEM` (integer)
`INI_ALL` (integer)
`M_E` (float)
`M_LOG2E` (float)
`M_LOG10E` (float)
`M_LN2` (float)
`M_LN10` (float)
`M_PI` (float)
`M_PI_2` (float)
`M_PI_4` (float)
`M_1_PI` (float)
`M_2_PI` (float)
`M_2_SQRTPI` (float)
`M_SQRT2` (float)
`M_SQRT1_2` (float)
`CRYPT_SALT_LENGTH` (integer)
`CRYPT_STD_DES` (integer)
`CRYPT_EXT_DES` (integer)
`CRYPT_MD5` (integer)
`CRYPT_BLOWFISH` (integer)
`DIRECTORY_SEPARATOR` (string)
`SEEK_SET` (integer)
`SEEK_CUR` (integer)
`SEEK_END` (integer)
`LOCK_SH` (integer)
`LOCK_EX` (integer)
`LOCK_UN` (integer)
`LOCK_NB` (integer)
`HTML_SPECIALCHARS` (integer)
`HTML_ENTITIES` (integer)
`ENT_COMPAT` (integer)
`ENT_QUOTES` (integer)
`ENT_NOQUOTES` (integer)
`INFO_GENERAL` (integer)
`INFO_CREDITS` (integer)
`INFO_CONFIGURATION` (integer)
`INFO_MODULES` (integer)
`INFO_ENVIRONMENT` (integer)
`INFO_VARIABLES` (integer)
`INFO_LICENSE` (integer)
`INFO_ALL` (integer)
`CREDITS_GROUP` (integer)
`CREDITS_GENERAL` (integer)
`CREDITS_SAPI` (integer)
`CREDITS_MODULES` (integer)
`CREDITS_DOCS` (integer)
`CREDITS_FULLPAGE` (integer)
`CREDITS_QA` (integer)
`CREDITS_ALL` (integer)
`STR_PAD_LEFT` (integer)
`STR_PAD_RIGHT` (integer)
`STR_PAD_BOTH` (integer)
`PATHINFO_DIRNAME` (integer)
`PATHINFO_BASENAME` (integer)
`PATHINFO_EXTENSION` (integer)
`PATH_SEPARATOR` (string)
`CHAR_MAX` (integer)
`LC_CTYPE` (integer)
`LC_NUMERIC` (integer)
`LC_TIME` (integer)
`LC_COLLATE` (integer)
`LC_MONETARY` (integer)
`LC_ALL` (integer)
`LC_MESSAGES` (integer)
`ABDAY_1` (integer)
`ABDAY_2` (integer)
`ABDAY_3` (integer)
`ABDAY_4` (integer)
`ABDAY_5` (integer)
`ABDAY_6` (integer)
`ABDAY_7` (integer)
`DAY_1` (integer)
`DAY_2` (integer)
`DAY_3` (integer)
`DAY_4` (integer)
`DAY_5` (integer)
`DAY_6` (integer)
`DAY_7` (integer)
`ABMON_1` (integer)
`ABMON_2` (integer)
`ABMON_3` (integer)
`ABMON_4` (integer)
`ABMON_5` (integer)
`ABMON_6` (integer)
`ABMON_7` (integer)
`ABMON_8` (integer)
`ABMON_9` (integer)
`ABMON_10` (integer)
`ABMON_11` (integer)
`ABMON_12` (integer)
`MON_1` (integer)
`MON_2` (integer)
`MON_3` (integer)
`MON_4` (integer)
`MON_5` (integer)
`MON_6` (integer)
`MON_7` (integer)
`MON_8` (integer)
`MON_9` (integer)
`MON_10` (integer)
`MON_11` (integer)
`MON_12` (integer)
`AM_STR` (integer)
`PM_STR` (integer)
`D_T_FMT` (integer)
`D_FMT` (integer)
`T_FMT` (integer)
`T_FMT_AMPM` (integer)
`ERA` (integer)
`ERA_YEAR` (integer)
`ERA_D_T_FMT` (integer)
`ERA_D_FMT` (integer)
`ERA_T_FMT` (integer)
`ALT_DIGITS` (integer)
`INT_CURR_SYMBOL` (integer)
`CURRENCY_SYMBOL` (integer)
`CRNCYSTR` (integer)
`MON_DECIMAL_POINT` (integer)
`MON_THOUSANDS_SEP` (integer)
`MON_GROUPING` (integer)
`POSITIVE_SIGN` (integer)
`NEGATIVE_SIGN` (integer)
`INT_FRAC_DIGITS` (integer)
`FRAC_DIGITS` (integer)
`P_CS_PRECEDES` (integer)
`P_SEP_BY_SPACE` (integer)
`N_CS_PRECEDES` (integer)
`N_SEP_BY_SPACE` (integer)
`P_SIGN_POSN` (integer)
`N_SIGN_POSN` (integer)
`DECIMAL_POINT` (integer)
`RADIXCHAR` (integer)
`THOUSANDS_SEP` (integer)
`THOUSEP` (integer)
`GROUPING` (integer)
`YESEXPR` (integer)
`NOEXPR` (integer)
`YESSTR` (integer)
`NOSTR` (integer)
`CODESET` (integer)
`LOG_EMERG` (integer)
`LOG_ALERT` (integer)
`LOG_CRIT` (integer)
`LOG_ERR` (integer)
`LOG_WARNING` (integer)
`LOG_NOTICE` (integer)
`LOG_INFO` (integer)
`LOG_DEBUG` (integer)
`LOG_KERN` (integer)
`LOG_USER` (integer)
`LOG_MAIL` (integer)
`LOG_DAEMON` (integer)
`LOG_AUTH` (integer)
`LOG_SYSLOG` (integer)
`LOG_LPR` (integer)
`LOG_NEWS` (integer)
`LOG_UUCP` (integer)
`LOG_CRON` (integer)
`LOG_AUTHPRIV` (integer)
`LOG_LOCAL0` (integer)
`LOG_LOCAL1` (integer)
`LOG_LOCAL2` (integer)
`LOG_LOCAL3` (integer)
`LOG_LOCAL4` (integer)
`LOG_LOCAL5` (integer)
`LOG_LOCAL6` (integer)
`LOG_LOCAL7` (integer)
`LOG_PID` (integer)
`LOG_CONS` (integer)
`LOG_ODELAY` (integer)
`LOG_NDELAY` (integer)
`LOG_NOWAIT` (integer)
`LOG_PERROR` (integer)