eventfd - Linux

Overview

eventfd allows creation and usage of eventfd objects. An eventfd object stores notification events which can be blocked upon or read from, and can be signaled or written to to wake up waiting processes.

Syntax

eventfd [-m] count

Options/Flags

• -m: Enable the creation of multiple eventfds in a single command.

Examples

Create a single eventfd object:

eventfd 1

Create multiple eventfds:

eventfd -m 10

Read from an eventfd object:

cat /proc/<pid>/fdinfo/<fd>

Write to an eventfd object:

echo 1 > /proc/<pid>/fdinfo/<fd>

Common Issues

• Eventfd object doesn’t exist:

  • Verify that the eventfd object exists in the file system.

• Unable to read/write to eventfd object:

  • Check the file permissions of the eventfd object.

Integration

Eventfd can be used with other commands to create and manipulate eventfd objects. For example:

• Create and read multiple eventfds:

eventfd -m 10 | xargs -n1 cat

Create and write to an eventfd:

eventfd 1 | xargs -n1 echo 1

Related Commands

• eventfd-read: Read from an eventfd object.
• eventfd-write: Write to an eventfd object.