.. zephyr:code-sample:: posix-eventfd
:name: eventfd()
Use ``eventfd()`` to create a file descriptor for event notification.
Overview
********
This sample application demonstrates using the POSIX eventfd() function to create a file descriptor,
which can be used for event notification. The returned file descriptor is used with write/read calls
and write/read values are output to the console.
Building and Running
********************
This project outputs to the console. It can be built and executed on QEMU as follows:
.. zephyr-app-commands::
:zephyr-app: samples/posix/eventfd
:host-os: unix
:board: qemu_x86
:goals: run
:compact:
For comparison, to build directly for your host OS if it is POSIX compliant (for ex. Linux):
.. code-block:: console
cd samples/posix/eventfd
make -f Makefile.host
The make output file will be located in samples/posix/eventfd/build.
Sample Output
=============
.. code-block:: console
Writing 1 to efd
Writing 2 to efd
Writing 3 to efd
Writing 4 to efd
Completed write loop
About to read
Read 10 (0xa) from efd
Finished
1b66353a8d