mcrypt_module_is_block_algorithm_mode(3) php man page | unix.com

MCRYPT_MODULE_IS_BLOCK_ALGORITHM_MODE(3)				 1				  MCRYPT_MODULE_IS_BLOCK_ALGORITHM_MODE(3)

mcrypt_module_is_block_algorithm_mode - Returns if the specified module is a block algorithm or not

SYNOPSIS
       bool mcrypt_module_is_block_algorithm_mode (string  $mode, [string  $lib_dir])

DESCRIPTION
	This function returns TRUE if the mode is for use with block algorithms, otherwise it returns FALSE. (e.g.  FALSE for stream, and TRUE for
       cbc, cfb, ofb).

PARAMETERS
	      o $mode
		- The mode to check.

	      o $lib_dir
		- The optional $lib_dir parameter can contain the location where the algorithm module is on the system.

RETURN VALUES
	This function returns TRUE if the mode is for use with block algorithms, otherwise it returns FALSE. (e.g.  FALSE for stream, and TRUE for
       cbc, cfb, ofb).

PHP Documentation Group 										  MCRYPT_MODULE_IS_BLOCK_ALGORITHM_MODE(3)