Php/docs/reserved.constants
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预定义常量
内核预定义常量
这些常量在 PHP 的内核中定义。它包含 PHP、Zend 引擎和 SAPI 模块。
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"). Available since PHP 5.2.7.
PHP_MINOR_VERSION(int)- 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(int)- 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(int)- 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(int)- Available since PHP 5.2.7.
PHP_DEBUG(int)- Available since PHP 5.2.7.
PHP_MAXPATHLEN(int)- The maximum length of filenames (including path) supported by this build of PHP. Available since PHP 5.3.0.
PHP_OS(string)- The operating system PHP was built for.
PHP_OS_FAMILY(string)- The operating system family PHP was built for. Either 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.参见 php_sapi_name()。
PHP_EOL(string)- 当前平台中对于换行符的定义。自 PHP 5.0.2 起可用
PHP_INT_MAX(int)- 当前 PHP 版本支持的最大整型数字。在 32 位系统中通常为 int(2147483647)，64 位系统中为 int(9223372036854775807)。自 PHP 5.0.5 起可用。
PHP_INT_MIN(int)- 当前 PHP 版本支持的最大整型数字。在 32 位系统中通常为 int(-2147483648)，64 系统中为 int(-9223372036854775808)。自 PHP 7.0.0 起可用。通常情况下 PHP_INT_MIN === ~PHP_INT_MAX。
PHP_INT_SIZE(int)- The size of an integer in bytes in this build of PHP. 自 PHP 5.0.5 起可用
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)PHP_PREFIX(string)- The value "--prefix" was set to at configure.
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).
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. Available since PHP 5.2.0
E_DEPRECATED(int)- Error reporting constant. Available since PHP 5.3.0
E_USER_DEPRECATED(int)- Error reporting constant. Available since PHP 5.3.0
E_ALL(int)- Error reporting constant
E_STRICT(int)- Error reporting constant
__COMPILER_HALT_OFFSET__(int)- 自 PHP 5.1.0 起有效
true(boolean)- See Booleans.
false(boolean)- See Booleans.
null(null)- See Null.
PHP_WINDOWS_EVENT_CTRL_C(int)- A Windows
CTRL+Cevent. Available as of PHP 7.4.0 (Windows only). PHP_WINDOWS_EVENT_CTRL_BREAK(int)- A Windows
CTRL+BREAKevent. Available as of PHP 7.4.0 (Windows only).
参见 魔术常量。
