Methods Requiring INOUT and OUT Arguments

Currently REXX supports only the following types as INOUT and OUT arguments: boolean, char, octet, short, ushort, long, ulong, float, double, and string. Because INOUT and OUT arguments actually update the object data directly, you must use special objects for these arguments. REXX provides a set of SOM objects specifically for these arguments.

For each supported INOUT or OUT argument type, there is a matching class that you must use to create the object for a method requiring that type of argument. New instances of these supplied classes have a default value of 0 or '' (a null string). The following table lists the types with the matching Class names and the default values assigned to new instances: ┌────────────────────────────────────────────────┐
│ Table 2. Class names for SOM types │
├────────────┬─────────────────┬─────────────────┤
│ CLASS NAME │ CLASS TYPE │ DEFAULT VALUE │
├────────────┼─────────────────┼─────────────────┤
│ boolean │ DLFBoolean │ 0 (false) │
├────────────┼─────────────────┼─────────────────┤
│ char │ DLFChar │ 0 (NULL) │
├────────────┼─────────────────┼─────────────────┤
│ octet │ DLFOctet │ 0 (NULL) │
├────────────┼─────────────────┼─────────────────┤
│ short │ DLFShort │ 0 │
├────────────┼─────────────────┼─────────────────┤
│ ushort │ DLFUShort │ 0 │
├────────────┼─────────────────┼─────────────────┤
│ long │ DLFLong │ 0 │
├────────────┼─────────────────┼─────────────────┤
│ ulong │ DLFULong │ 0 │
├────────────┼─────────────────┼─────────────────┤
│ float │ DLFFloat │ 0 │
├────────────┼─────────────────┼─────────────────┤
│ double │ DLFDouble │ 0 │
├────────────┼─────────────────┼─────────────────┤
│ string │ DLFString │ '' (a null │
│ │ │ string) │
└────────────┴─────────────────┴─────────────────┘

This means that to call a method that requires an INOUT argument of type long, you must pass an object of the DLFLong class as the argument for that method. This restriction is only for INOUT and OUT arguments; for any IN argument you can specify an instance of any of the special classes or appropriate REXX classes.

To use any of the special classes within REXX you simply need to import the classes (see Importing SOM Classes).

All instances of these classes support the following methods:

• get_value
  Retrieves the current value of the object.
  _set_value(newValue)
  Sets the current value of the object to newValue.
  asString
  Retrieves a string representation of the current value.

  In addition, DLFString has the following methods:

• get_maxSize
  Is the length of the largest string that can be stored into the object, when using this object as an INOUT or OUT parameter.
  _set_maxSize(size)
  Makes size the length of the largest string that can be stored into the object, when using this object as an INOUT or OUT parameter. If _set_value is called with a string longer than size, it calls _set_maxSize with the new larger value.

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