Procedures as arguments. The arguments in a procedure statement are called dummy arguments. The data type and rank of actual and dummy arguments must correspond. May only be referenced by their host. May invoke other procedures including those internal to the same host.
External procedures Have no host.
May invoke other procedures. May contain internal procedures. By default no variable declared inside a procedure retains its value from one call to the next. Variables with initial values automatically acquire the SAVE attribute. It is not possible to SAVE dummy arguments or function results.