Hello World Example

The Hello, World sample introduces a Fuchsia component that prints “Hello, world” messages to the system log. The BUILD.gn file contains rules that demonstrate building a single binar with shared and static libraries as dependencies.

Source layout

• hello.cc: Main entrypoint for the component binary
• hello_shared: Shared library exposing functions to retrieve a greeting
• hello_static: Static library exposing functions to retrieve a greeting

Before you begin

1. Start a FEMU instance:

   $ ./third_party/fuchsia-sdk/bin/femu.sh -N
   

2. Start a local package repository instance:

   $ ./third_party/fuchsia-sdk/bin/fserve.sh --image qemu-x64
   

Build the sample

1. Run the build script to compile and package the sample:

   $ ./scripts/build.sh
   

2. Publish the FAR package to your local package repository:

   $ ./third_party/fuchsia-sdk/bin/fpublish.sh out/x64/hello_world.far
   

Run the sample

1. Launch the sample component using ffx component run. This resolves the component from the package repository and starts it:

   $ ffx component run fuchsia-pkg://fuchsia.com/hello_world#meta/hello_world.cm
   

2. View the greeting messages in the system log using ffx target log:

   $ ffx target log watch
   ...
   [hello_world][I] pthreads: hello
   [hello_world][I] Hello, world
   [hello_world][I] cppthreads: hello