tree: 21b1efff88e66a4689dc1ea733b8754fa53974e5 [path history] [tgz]
  1. README.md
  2. cpp/
  3. meta/
sdk/lib/sys/service/README.md

lib/fidl-service

A support library for FIDL service directories.

Purpose

The purpose of this library is to provide a way to both consume or publish FIDL service directories. That is, this library provides the building blocks for developing clients or servers of FIDL service directories.

A FIDL service directory is a way to represent a FIDL service within the namespace of a process. For example, take the following FIDL service:

library fuchsia.examples;

using fidl.examples.echo;

service MyService {
  fidl.examples.echo.Echo regular_echo;
  fidl.examples.echo.Echo reversed_echo;
};

The FIDL service named MyService can be represented within the namespace of a process with the following structure:

/svc/fuchsia.examples.MyService
/svc/fuchsia.examples.MyService/default
/svc/fuchsia.examples.MyService/default/regular
/svc/fuchsia.examples.MyService/default/reversed
/svc/fuchsia.examples.MyService/alternate
/svc/fuchsia.examples.MyService/alternate/regular
/svc/fuchsia.examples.MyService/alternate/reversed

Here we can see that MyService has two instances, default and alternate, and each instance has the members regular and reversed.

Using this library, we can interact we can interact with FIDL service directories in code more simply. For example, here is how we would open the alternate instance of MyService and bind to the member regular:

auto alternate = fidl::OpenService<fuchsia::examples::MyService>("alternate");
auto regular = alternate.regular_echo().Connect().Bind();

For more examples, please see //examples/fidl.

Dependencies

This library depends on:

  • fuchsia.io - This is required to use fuchsia::io::Directory.
  • lib/async - This is required to use async::WaitMethod.
  • lib/fdio - This is required to use fdio_ns_t.
  • lib/fidl - This is required to interact with FIDL.
  • lib/vfs - This required to use vfs::PseudoDir.

Generated FIDL service code will depend on this library, and therefore inherit the same set of dependencies.

Additionally, server processes may want to use lib/sys in order to simplify their implementation.