---
title: "proc_parent()"
description: "Returns the parent handle of the supplied process."
url: "https://wasix.org/docs/api-reference/wasix/proc_parent/"
markdown: "https://wasix.org/docs/api-reference/wasix/proc_parent.md"
---

# `proc_parent()`

Returns the parent handle of the supplied process.

## Description

The `proc_parent()` function is used to retrieve the parent handle of a given process. It takes a process identifier (PID) as input and returns the PID of the parent process.

In POSIX systems, each process has a parent process except for the initial process, which is typically assigned a parent of PID 1 (init process). The parent process is responsible for creating and managing its child processes.

## Syntax

```ebnf
  ;;; Returns the parent handle of a particular process
  (@interface func (export "proc_parent")
    ;;; Handle of the process to get the parent handle for
    (param $pid $pid)
    (result $error (expected $pid (error $errno)))
  )
```

## Parameters

- `ctx`: The function environment.
- `pid`: The process identifier (PID) of the process whose parent is to be retrieved.
- `ret_parent`: Pointer to store the returned parent process ID.

## Return Value

The function returns an `Errno` value indicating the result of the operation. If the operation is successful, it returns `Errno::Success`. If the supplied process does not exist or the current process is not the parent, it returns `Errno::Badf`.

## Logging

This function is instrumented with `debug` level logging. It includes the following field for debugging purposes:

- `pid`: The process identifier (PID) of the supplied process.
- `parent`: The parent process ID.

## Note

- The `proc_parent()` function is used to retrieve the parent handle of a given process.
- It checks if the supplied `pid` matches the current process’s PID. If they match, it retrieves the parent PID using the `ppid()` method of the current process.
- If the supplied `pid` does not match the current process’s PID, it attempts to retrieve the process from the control plane using the `get_process()` method.
- The function stores the parent PID in the specified `ret_parent` pointer.
- The function returns `Errno::Badf` if the supplied process does not exist or the current process is not the parent.

---

[Documentation index](https://wasix.org/llms.txt) · [HTML version](https://wasix.org/docs/api-reference/wasix/proc_parent/)