# Process runtime reference

_Peios / Developing for Peios / Process runtime reference_

> Developer contracts for process creation, program replacement, termination, child collection, orphan adoption, and per-thread operations.

Use this reference when implementing a launcher, supervisor, threading library,
or other code that creates and controls processes. For inspecting or stopping a
running program, start with [Task Manager](/peios/using-peios/threads-and-processes/task-manager.md)
and [Process lifecycle](/peios/using-peios/threads-and-processes/process-lifecycle.md).

- [Process creation](/peios/developing-for-peios/process-runtime-reference/process-creation-reference.md):
  `fork`, `vfork`, `clone`/`clone3`, sharing flags, `exec`, `posix_spawn`, and pidfds.
- [Process lifecycle](/peios/developing-for-peios/process-runtime-reference/process-lifecycle-reference.md):
  termination, exit-status encoding, the wait family, and subreaper adoption.
- [Thread operations](/peios/developing-for-peios/process-runtime-reference/thread-operations-reference.md):
  TIDs, thread-exit notification, and thread-local storage.

These calls also interact with Peios security. See
[Token lifecycle](/peios/security-fundamentals/tokens/lifecycle.md) for identity
inheritance, [the process security descriptor](/peios/security-fundamentals/process-integrity-protection/the-process-security-descriptor.md)
for process rights, and [the two-check rule](/peios/security-fundamentals/process-integrity-protection/the-two-check-rule.md)
for cross-process access.

Related content:

- [Process creation reference](/peios/developing-for-peios/process-runtime-reference/process-creation-reference.md)
- [Process lifecycle reference](/peios/developing-for-peios/process-runtime-reference/process-lifecycle-reference.md)
- [Thread operations reference](/peios/developing-for-peios/process-runtime-reference/thread-operations-reference.md)
- [Task Manager](/peios/using-peios/threads-and-processes/task-manager.md)