Stdlib module kernel/fileio.vitl

Overview

`kernel/fileio.vitl` is a public stdlib surface inside the `kernel` family. It should be read as one focused slice of the broader family responsibility: System-facing runtime helpers such as process, scheduler, threads, sync, users, signals, network, device, and memory.

Purpose

This file should be chosen because of responsibility, not because its name “sounds close enough”. Inside the kernel family, it carries one focused part of the contract and keeps that responsibility separate from neighboring concerns.

• Use this module when bytes or paths cross a host boundary and architecture must keep that boundary visible.
• A service manager may use scheduler, process, and signals while keeping policy in separate code.
• A network-facing runtime should explain why it depends on kernel surfaces instead of lighter families.

Taxonomy

Think of this page as a generated encyclopedia entry rather than a hand-written tutorial. The goal is to show what kind of module this is, how dense it is, and what reading strategy makes sense before depending on it.

• Large algorithm surface: this file exposes many procedures and likely acts as a domain toolkit rather than a single thin wrapper.
• Owns domain vocabulary: the module declares data shapes in addition to executable helpers, so its types are part of the contract.
• Has tuning constants: part of the module behavior is controlled by named constants that document default precision, limits, or policy.
• Minimal top-level dependencies: the module reads as mostly self-contained from its opening declarations.
• Explicit export surface: the file ends with visible export declarations instead of relying only on implicit namespace discovery.

Implementation profile

This profile is inferred directly from the source text. It does not replace reading the file, but it tells you quickly whether the module is mostly declarative, loop-heavy, branch-heavy, or organized around many small exits.

Top-level API inventory

Imported surfaces

This file does not advertise a top-level `use` surface in its opening declarations. That often means it is either self-contained or an aggregation layer.

Position in family

This file is module 3 of 12 in the kernel family when ordered by path. By procedure count it ranks 2, and by line count it ranks 1. Those ranks are useful as rough signals of breadth, not as quality judgments.

Declaration map

The declaration map turns raw source into a scan-friendly catalog. It is useful when the file is large enough that a reader wants to orient by kinds of surfaces first.

The table is exhaustive for top-level declarations of the selected kinds. This file declares 78 matching surfaces.

Representative signatures

These signatures are shown in source order so the page keeps the feel of a reference manual, not just a keyword cloud.

• const STDIN_FILENO: i32 = 0 (line 9)
• const STDOUT_FILENO: i32 = 1 (line 10)
• const STDERR_FILENO: i32 = 2 (line 11)
• const O_RDONLY: i32 = 0 (line 14)
• const O_WRONLY: i32 = 1 (line 15)
• const O_RDWR: i32 = 2 (line 16)
• const O_APPEND: i32 = 1024 (line 17)
• const O_CREAT: i32 = 64 (line 18)
• const O_EXCL: i32 = 128 (line 19)
• const O_TRUNC: i32 = 512 (line 20)
• const O_NONBLOCK: i32 = 2048 (line 21)
• const O_SYNC: i32 = 4096 (line 22)
• const S_IRUSR: i32 = 256 (line 25)
• const S_IWUSR: i32 = 128 (line 26)
• const S_IXUSR: i32 = 64 (line 27)
• const S_IRGRP: i32 = 32 (line 28)
• const S_IWGRP: i32 = 16 (line 29)
• const S_IXGRP: i32 = 8 (line 30)

The list is intentionally capped here; the source file declares 77 matching signatures in total.

How to use this module

Start by reading the file as an ownership boundary. Ask three questions: what enters this module, what stable types or procedures it exports, and what adjacent module should stay outside of it.

1. Read space and top-level imports first so the ownership boundary of kernel/fileio.vitl is explicit.
2. Scan constants before procedures; they often encode precision, limits, or policy assumptions that explain later behavior.
3. Read declared forms and picks before algorithms so the data vocabulary is stable in your head.
4. Traverse procedures in source order; the early helpers usually explain the naming and numeric conventions used later.
5. Use the source landmarks section below as a table of contents when the file is large.

User example

This example is generated from the actual stdlib module surface. Its job is not to be the smallest snippet possible; its job is to show a realistic consumer-shaped file that exercises the module and mirrors the language keywords the module itself relies on.

space demo/kernel_fileio
const SAMPLE_LABEL: string = "demo"
form UserReport {
  label: string,
  ready: bool
}
proc run_example() -> UserReport {
  let stable: bool = ready and true
    give UserReport { label: "ok", ready: ready }
}
export run_example

Keyword coverage

This table makes the “all keywords of the module” requirement auditable. It compares the detected Vitte keywords in the source file with the generated consumer example above.

Keywords still not exercised directly in the generated snippet: return, at. The page still lists them here so the gap is visible.

Source shape

space vitte/kernel_name/fileio
// File descriptor constants
const STDIN_FILENO: i32 = 0
const STDOUT_FILENO: i32 = 1
const STDERR_FILENO: i32 = 2
// File open flag_bits
const O_RDONLY: i32 = 0
const O_WRONLY: i32 = 1
const O_RDWR: i32 = 2
const O_APPEND: i32 = 1024

The excerpt is not meant to replace the file. It exists to make the module recognizable at first glance, the same way a Wikipedia infobox helps the reader orient before reading the whole article.

Source landmarks

Large files are easier to retain when they have visible landmarks. When the source contains explicit section banners, they are surfaced here; otherwise the first major declarations are used as anchors.

• Kernel File I/O — File descriptor operations, / Directory operations, file system management
• File Descriptor Operations
• File Descriptor Control
• Directory Operations
• File Management
• File Information
• File System Operations

Source organization

When a file carries its own internal chaptering, those chapters usually reveal the intended reading order better than a flat symbol list. This section reconstructs that organization from the source itself.

Complete API catalog

This catalog is the exhaustive file-level index for the module. It is intentionally closer to a generated encyclopedia appendix than to a tutorial summary.

Constants

Data surfaces

Procedures

Exports

Integration boundaries

Within kernel, this file should remain focused. If a future helper changes the host boundary, scheduling boundary, or data-shape boundary, it probably belongs in a neighbor module instead of being added here by convenience.

• Family responsibility: System-facing runtime helpers such as process, scheduler, threads, sync, users, signals, network, device, and memory.
• Family architecture role: Use `kernel` when the program explicitly models system services, scheduling, process behavior, or device-facing coordination.

Composition guidance

Choose this module when

• Choose kernel/fileio.vitl when the main question is owned by this module rather than by transport, storage, orchestration, or user-interface code.
• Use this module when bytes or paths cross a host boundary and architecture must keep that boundary visible.
• A service manager may use scheduler, process, and signals while keeping policy in separate code.
• A network-facing runtime should explain why it depends on kernel surfaces instead of lighter families.

Pause before extending it when

• Avoid extending this file when the new helper mostly changes the boundary to host I/O, runtime coordination, or foreign integration instead of staying inside kernel.
• Check nearby modules such as kernel/device.vitl, kernel/interrupt.vitl, kernel/memory.vitl before adding convenience wrappers here.

Relationship table

This table keeps the page closer to a real encyclopedia entry: a module is easier to understand when compared with its nearest alternatives in the same family.

Neighbor modules

• kernel/device.vitl
• kernel/interrupt.vitl
• kernel/memory.vitl
• kernel/network.vitl
• kernel/process.vitl
• kernel/scheduler.vitl
• kernel/signals.vitl
• kernel/sync.vitl