pthreads
PHP Manual

Constantes pré-definidas

As contantes abaixo são definidas por esta extensão e somente estarão disponíveis quando a extensão foi compilada com o PHP ou carregada dinamicamente durante a execução.

The following constants are for selective inheritance:

PTHREADS_INHERIT_ALL (integer)
The default inheritance mask used when starting Threads and Workers
PTHREADS_INHERIT_INI (integer)
Determines wether the ini entries are inherited by the new context
PTHREADS_INHERIT_CONSTANTS (integer)
Determines wether the constants are inherited by the new context
PTHREADS_INHERIT_CLASSES (integer)
Determines wether the class table is inherited by the new context
PTHREADS_INHERIT_FUNCTIONS (integer)
Determines wether the function table is inherited by the new context
PTHREADS_INHERIT_INCLUDES (integer)
Determines wether the included_files table is inherit by the new context
PTHREADS_INHERIT_NONE (integer)
Nothing will be inherited by the new context

pthreads
PHP Manual