The NamedValue structure

The NamedValue structure is defined in C as:

typedef unsigned long Flags;

struct NamedValue {
        Identifier  name;         // argument name
        any         argument;     // argument
        long        len;          // length/count of arg value
        Flags       arg_modes;    // argument mode flags
};

where: name is an Identifier string as defined in the CORBA specification, and argument is an any structure with the following declaration:

        struct any {
                TypeCode        _type;
                void*           _value;
        };

_type is a TypeCode, which has an opaque representation with operations defined on it to allow access to its constituent parts. Essentially the Typecode is composed of a field specifying the CORBA type represented and possibly additional fields needed to fully describe the type. See Chapter 7 of this manual for a complete explanation of TypeCodes.

_value is a pointer to the value of the any structure. Important: The contents of "_value" should always be a pointer to the value, regardless of whether the value is a primitive, a structure, or is itself a pointer (as in the case of object references, strings and arrays). For object references, strings and arrays, _value should contain pointer to the pointer that references the value. For example:

        string          testString;
        any             testAny;

        testAny._value = &testString;

len is the number of bytes that the argument value occupies. The following table gives the length of data values for the C language bindings. The value of len must be consistent with the TypeCode.

Data type               Length
short                   sizeof(short)
unsigned short          sizeof(unsigned short)
long                    sizeof(long)
unsigned long           sizeof(unsigned long)
float                   sizeof(float)
double                  sizeof(double)
char                    sizeof(char)
boolean                 sizeof(boolean)
octet                   sizeof(octet)
string                  strlen(string) - does not include '\0' byte
enum E{}                sizeof(unsigned long)
union U                 sizeof(U)
struct S{}              sizeof(S)
Object                  1
array N of type T1      Length(T1)*N
sequence V of type T2   Length(T2)*V - V is the actual # of elements

The arg_modes field is a bitmask (unsigned long) and may contain the following flag values:

ARG_IN              the associated value is an input-only argument
ARG_OUT             the associated value is an output-only argument
ARG_INOUT           the associated argument is an in/out argument

These flag values identify the parameter passing mode for the arguments. Additional flag values have specific meanings for Request and NVList methods and are listed with their associated methods.