Interface declarations

• Interface declarations define interface objects of a precisely defined type.
• Interface objects are interface constants, interface signals, interface variables and interface files.

interface_element { ; interface_element }

• interface_declaration

• interface_constant_declaration
• interface_signal_declaration
• interface_variable_declaration
• interface_file_declaration

[ constant ] identifier_list : [ in ] subtype_indication [ := static _expression ]

[ signal ] identifier_list : [ mode ] subtype_indication [ bus ] [ := static _expression ]

– subtype_indication must not be a file or pointer type.

[ variable ] identifier_list : [ mode ] subtype_indication [ := static _expression ]

file identifier_list : subtype_indication

– subtype_indication have to indicate a subtype of a file type.

• in – Ports cannot be written; default mode
• out – Ports cannot be read
• inout – Ports can be read and written
• buffer – Ports can be read but only be written by one source
• linkage – Ports can be read and written, but only as “actuals”.