php man page for zend_thread_id

ZEND_THREAD_ID(3)							 1							 ZEND_THREAD_ID(3)

zend_thread_id - Returns a unique identifier for the current thread

SYNOPSIS
       int zend_thread_id (void  )

DESCRIPTION
	This function returns a unique identifier for the current thread.

RETURN VALUES
	Returns the thread id as an integer.

EXAMPLES
       Example #1

	      zend_thread_id(3) example

	      <?php
	      $thread_id = zend_thread_id();

	      echo 'Current thread id is: ' . $thread_id;
	      ?>

	      The above example will output something similar to:

	      Current thread id is: 7864

NOTES
       Note

	       This function is only available if PHP has been built with ZTS (Zend Thread Safety) support and debug mode ( --enable-debug).

PHP Documentation Group 													 ZEND_THREAD_ID(3)