---
name: "pseudofs"
section: "9"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["linux", "freebsd"]
url: "https://new.carta.tech/pseudofs"
---

# pseudofs(9)

pseudo file system construction kit

## NAME

**pseudofs** – pseudo file system construction kit

## SYNOPSIS

**#include \<fs/pseudofs/pseudofs.h\>**

## DESCRIPTION

The **pseudofs** module offers an abstract API for pseudo-file systems such as [procfs(4)](/procfs/4.md) and [linprocfs(4)](/linprocfs/4.md). It takes care of all the hairy bits like interfacing with the VFS system, enforcing access control, keeping track of file numbers, and cloning files and directories that are process-specific. The consumer module, i.e., the module that implements the actual guts of the file system, needs only provide the directory structure (represented by a collection of structures declared and initialized by macros provided by **pseudofs**) and callbacks that report file attributes or write the actual file contents into sbufs.

## SEE ALSO

[linprocfs(4)](/linprocfs/4.md), [linsysfs(4)](/linsysfs/4.md), [procfs(4)](/procfs/4.md), [sbuf(9)](/sbuf/9.md), [vnode(9)](/vnode/9.md)

## HISTORY

The **pseudofs** module appeared in FreeBSD 5.0.

## AUTHORS

The **pseudofs** module and this manual page were written by Dag-Erling Smørgrav ⟨*des@FreeBSD.org*⟩.