mcrypt_module_is_block_mode This function returns if the the specified mode outputs blocks or not boolmcrypt_module_is_block_mode stringmode stringlib_dir This function returns &true; if the mode outputs blocks of bytes or &false; if it outputs just bytes. (eg. 1 for cbc and ecb, and 0 for cfb and stream). The optional lib_dir parameter can contain the location where the mode module is on the system.