All interfaces implemented in a solution must be described in IDL files. Each IDL file consists of a package of declarations in the IDL language.
An IDL file contains the following sections:
The only mandatory section.
A package name declaration has the following format:
package <name of the described package>
A package name can be composite. In this case, it is used to generate a path to the IDL file, for example:
/* Module.idl located at: a/b/c/Module.idl */
package a.b.c.Module
A package import statement has the following format:
import <name of external package>
It enables you to enter the following elements of an external package into the scope of an IDL file: named constants and user-defined types, including structures and variant types.
An interface declaration has the following syntax:
interface <interface name> {
<Declaration of methods>
}
The curly brackets contain declarations of methods that have the following syntax:
<Method name> (<arguments>)
Arguments are divided into input (in) and output (out) and are separated with a comma. Example declaration of the IPing interface:
interface IPing {
/* Ping method declaration
Ping(in UInt32 value, out UInt32 result);
}
IDL supports single-line comments and multi-line C++-style comments.
Examples of IDL files
In the simplest case, an IDL description contains only the package name and interface declaration:
ping.idl
/* ping – package name */
package ping
/* IPing interface declaration */
interface IPing {
/* Ping method declaration
Ping(in UInt32 value, out UInt32 result);
}
Example of a more complex IDL description:
Foo.idl
// Package name declaration
package Foo
// Package import statements
import Bar1
import Bar2
// Declaration of named constant
const UInt32 MaxStringSize = 1024;
// Declaration of synonym for user-defined type
typedef sequence <Char, MaxStringSize> String;
// Declaration of structure
struct BazInfo {
Char x;
array <String, 100> y;
sequence <sequence <UInt32, 100>, 200> y;
}
// Declaration of interfaces
interface IFoo {
foo (in UInt32 a);
bar (in UInt32 a, out UInt32 b1, out UInt8 b2);
}
interface IBaz {
baz (in BazInfo a, out UInt32 b);
}
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