code: public function getGuid()
  	{
  		return sprintf(
  						'%04x%04x-%04x-%03x4-%04x-%04x%04x%04x',
  						mt_rand(0, 65535),
  						mt_rand(0, 65535),	// 32 bits for "time_low"
  						mt_rand(0, 65535),	// 16 bits for "time_mid"
  						mt_rand(0, 4095),	// 12 bits before the 0100 of (version) 4 for "time_hi_and_version"
  						bindec(substr_replace(sprintf('%016b', mt_rand(0, 65535)), '01', 6, 2)),
  						// 8 bits, the last two of which (positions 6 and 7) are 01, for "clk_seq_hi_res"
  						// (hence, the 2nd hex digit after the 3rd hyphen can only be 1, 5, 9 or d)
  						// 8 bits for "clk_seq_low"
  						mt_rand(0, 65535),
  						mt_rand(0, 65535),
  						mt_rand(0, 65535) // 48 bits for "node"
  		);
  	}
docs: Generate a GUID.
  
  @return string