下列常量作为 PHP 核心的一部分总是可用的。
PHP_OUTPUT_HANDLER_START
(integer)
Indicates that output buffering has begun.
PHP_OUTPUT_HANDLER_WRITE
(integer)
Indicates that the output buffer is being flushed, and had data to output.
Available since PHP 5.4.
PHP_OUTPUT_HANDLER_FLUSH
(integer)
Indicates that the buffer has been flushed.
Available since PHP 5.4.
PHP_OUTPUT_HANDLER_CLEAN
(integer)
Indicates that the output buffer has been cleaned.
Available since PHP 5.4.
PHP_OUTPUT_HANDLER_FINAL
(integer)
Indicates that this is the final output buffering operation.
Available since PHP 5.4.
PHP_OUTPUT_HANDLER_CONT
(integer)
Indicates that the buffer has been flushed, but output buffering will continue.
As of PHP 5.4, this is an alias for
PHP_OUTPUT_HANDLER_WRITE.
PHP_OUTPUT_HANDLER_END
(integer)
Indicates that output buffering has ended.
As of PHP 5.4, this is an alias for
PHP_OUTPUT_HANDLER_FINAL.
PHP_OUTPUT_HANDLER_CLEANABLE
(integer)
Controls whether an output buffer created by ob_start() can be cleaned.
Available since PHP 5.4.
PHP_OUTPUT_HANDLER_FLUSHABLE
(integer)
Controls whether an output buffer created by ob_start() can be flushed.
Available since PHP 5.4.
PHP_OUTPUT_HANDLER_REMOVABLE
(integer)
Controls whether an output buffer created by ob_start() can be removed before the end of the script.
Available since PHP 5.4.
PHP_OUTPUT_HANDLER_STDFLAGS
(integer)
The default set of output buffer flags; currently equivalent to
PHP_OUTPUT_HANDLER_CLEANABLE |
PHP_OUTPUT_HANDLER_FLUSHABLE |
PHP_OUTPUT_HANDLER_REMOVABLE.
Available since PHP 5.4.