== Write the IPDL "Hello, world" protocol ==
(No, this isn't the traditional "Hello, world" example. IPDL lacks facilities for printing. I'm taking some poetic license.)
You should be familiar with the following IPDL specification. If not, you should re-read the [[IPDL/Getting started guide]]. Copy the code into <code>ipc/test-harness/Test.ipdl</code>.
namespace mozilla {
namespace test {
protocol Test
{
child:
Hello();
parent:
World();
};
} // namespace test
} // namespace mozilla
We will use this specification to make a C++ program in which the parent sends the child the Hello() message, and the child prints "Hello, " to stdout. The child will then send the parent the World() message, and the parent will print "world!" to stdout.
== Run the IPDL compiler ==