18.2.4 Mapping for String Types

   CORBA currently defines the data type string to represent strings that consist of 8-bit quantities, which are NULL-terminated.

   Microsoft IDL and ODL define a number of different data types, which are used to represent both 8-bit character strings and strings containing wide characters based on Unicode.

    Table 18-2 illustrates how to map the string data types in OMG IDL to their corresponding data types in both Microsoft IDL and ODL.

   Table 18-2 OMG IDL to Microsoft IDL/ODL String Mappings

   OMG IDL supports two different types of strings: bounded and unbounded. Bounded strings are defined as strings that have a maximum length specified; whereas, unbounded strings do not have a maximum length specified.

   18.2.4.1 Mapping for Unbounded String Types

   The definition of an unbounded string limited to 8-bit quantities in OMG IDL

    // OMG IDL typedef string UNBOUNDED_STRING;

   is mapped to the following syntax in Microsoft IDL and ODL, which denotes the type of a “stringified unique pointer to character.?

    // Microsoft IDL and ODLtypedef [string, unique] char * UNBOUNDED_STRING;

   In other words, a value of type UNBOUNDED_STRING is a non-NULL pointer to a one-dimensional null-terminated character array whose extent and number of valid elements can vary at run-time.

   18.2.4.2 Mapping for Bounded String Types

   Bounded strings have a slightly different mapping between OMG IDL and Microsoft IDL and ODL. The following OMG IDL definition for a bounded string:

   // OMG IDL const long N = ...; typedef string<N> BOUNDED_STRING;

   maps to the following syntax in Microsoft IDL and ODL for a “stringified nonconformant array.?

   // Microsoft IDL and ODL const long N = ... ; typedef [string, unique] char (* BOUNDED_STRING) [N];

   In other words, the encoding for a value of type BOUNDED_STRING is that of a null-terminated array of characters whose extent is known at compile time, and the number of valid characters can vary at run-time.