WAIT_FOR_ALL_PIPES

This configuration variable determines if the runtime calls the wait system call each time a -P file is closed. When WAIT_FOR_ALL_PIPES is set to 0 (off, false, no), the runtime does not make this call until it is ready to close the last pipe it knows about. Setting this configuration variable to the default 1 (on, true, yes) means that the runtime calls the wait system call when a -P file is closed.