Feature
|
IN
|
OUT
|
INOUT
|
---|---|---|---|
Default/specified
|
Default.
|
Must be specified.
|
Must be specified.
|
Operation
|
Passes values to a subprogram.
|
Returns values to the caller.
|
Passes initial values to a subprogram; returns updated values to the caller.
|
Action
|
Formal parameter, acts like a constant.
|
Formal parameter, acts like an uninitialized variable.
|
Formal parameter, acts like an initialized variable.
|
Value assignation
|
Formal parameter, cannot be assigned a value.
|
Formal parameter, cannot be used in an expression; must be assigned a value.
|
Formal parameter, should be assigned a value.
|
Parameter type
|
Actual parameter, can be a constant, initialized variable, literal, or expression.
|
Actual parameter, must be a variable.
|
Actual parameter, must be a variable.
|