# Objc Coding Practices

> Use when authoring or reviewing Objective-C, Google/GitHub layout, 3+ char prefixes, property/copy semantics, designated initializers, Doxygen docs, NSError errors, literals, and clang-format/static analysis in CI.

- Skill: `ryan-brosas/objc-coding-practices` (Agent Skill)
- Install (CLI): `npx skillmds@latest add ryan-brosas/objc-coding-practices`
- Raw SKILL.md: https://api.skillmd.com/api/skills/ryan-brosas/objc-coding-practices/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: ryan-brosas (https://skillmd.com/u/ryan-brosas)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/ryan-brosas/objc-coding-practices

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# Objective-C Coding Practices

Application skill for Objective-C style learning (from the archived `awesome-guidelines` style capsules). Follow Apple Cocoa Coding Guidelines plus project `clang-format`; GitHub tab legacy trees normalize via formatter over time.

## Core Principle

Objective-C quality is **prefixed, documented headers with explicit ownership**, copy immutables, designated inits, NSError for expected failures.

## When to Use / NOT

- iOS/macOS ObjC and ObjC++ (`.m`, `.mm`) libraries and app code.
- Setting up clang-format, clang-tidy, OCLint, Xcode analyze in CI.

**NOT when:**

- Swift-only modules, use Swift style foundations.
- Generated ObjC stubs, validate generators.

## Workflow

1. **Layout**, indent, braces, imports (`objc-style-formatting-layout.md`).
2. **Naming**, prefixes, categories (`objc-style-naming-prefixes.md`).
3. **Memory**, properties, init, copy (`objc-style-properties-memory.md`).
4. **Docs/errors**, Doxygen, NSError (`objc-style-docs-errors.md`).
5. **Verify**, clang-format, analyzer, header doc audit on exports.

## Red Flags

- Two-letter class prefix
- Unprefixed category methods on shared types
- `getFoo` accessor naming
- Dot syntax on non-property methods
- Missing memory semantics on properties
- `@synthesize` without compiler requirement
- Iv ar access outside init/dealloc/custom accessor
- Messaging `self` in `-init`/`-dealloc` for overridable selectors
- `+new` usage
- Redundant ivar nil/zero initialization in init
- Individual Foundation subheaders instead of umbrella import
- `#include` on ObjC headers
- Unsigned down-count loops
- Macro constants where `static const` suffices
- Exceptions for normal control flow
- Undocumented public methods/properties
- Returning mutable where immutable contract promised
- No copy of mutable args in setters/async
- Weak long-lived references (refactor target)
- Mixed selector wrapping styles in one file
- Tomdoc/Doxygen missing nil documentation on object params

## Verification

- `clang-format --dry-run` / Xcode format on changed files
- `xcodebuild analyze` or project static analyzer
- Public header Doxygen/nil-contract audit
- Capsule checklist on prefix + designated initializer chain


## References

- `awesome-guidelines/references/objc-style-learning-note.md`
- `awesome-guidelines/references/objc-style-formatting-layout.md`
- `awesome-guidelines/references/objc-style-naming-prefixes.md`
- `awesome-guidelines/references/objc-style-properties-memory.md`
- `awesome-guidelines/references/objc-style-docs-errors.md`