---
id: php-variables-scope
title: "PHP Variables Scope"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["PHP 변수 범위", "global keyword", "static keyword"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.9
created_at: 2026-07-04
updated_at: 2026-07-04
review_reason: ""
merge_history: []
tags: ["php", "programming", "w3schools", "scope"]
raw_sources: ["https://www.w3schools.com/php/php_variables_scope.asp"]
applied_in: []
github_commit: ""
---

# [[PHP Variables Scope]]

## 🎯 한 줄 통찰 (One-line insight)
`static` variables break the normal "destroyed on function exit" rule — a static local variable retains its value between separate calls to the same function, meaning `static $x = 0; $x++;` accumulates across calls even though it's still only accessible inside that one function (local scope + persistent state, a combination unique to static). [S1]

## 🧠 핵심 개념 (Core concepts)
- **Global scope** — a variable declared outside any function; NOT accessible inside functions by default. [S1]
- **Local scope** — a variable declared inside a function; created on call, destroyed on function exit. [S1]
- **Static scope** — `static $x = 0;` preserves the variable's value across multiple calls to the same function, while remaining local (inaccessible outside). [S1]
- **`global` keyword** — inside a function, declares that a name refers to the global variable rather than creating a new local one. [S1]
- **`$GLOBALS` superglobal** — an array holding all global variables, accessible and mutable from inside any function without the `global` keyword. [S1]

## 📖 세부 내용 (Details)
- Global scope inaccessible inside function: `$x = 5; function myTest() { echo "Variable x inside function is: $x"; } // does not print 5`. [S1]
- Local scope: `function myTest() { $x = 5; echo "Variable x inside function is: $x"; } // $x undefined outside`. [S1]
- Static persists across calls: `function myTest() { static $x = 0; echo $x; $x++; } myTest(); myTest(); myTest(); // 0 1 2`. [S1]
- global keyword: `$x = 5; $y = 10; function myTest() { global $x, $y; $y = $x + $y; } myTest(); echo $y; // 15`. [S1]
- $GLOBALS equivalent: `function myTest() { $GLOBALS['y'] = $GLOBALS['x'] + $GLOBALS['y']; } myTest(); echo $y; // 15`. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
- **static의 예외적 지속성**: 함수 종료 시 일반 지역변수는 삭제되지만 static 변수는 값을 유지하며, 여전히 함수 지역 범위에 한정된다는 이중적 특성이 명시됨. [S1]

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — 호출 횟수를 세는 카운터(static $x)가 정적 스코프 활용의 대표 사례다. [S1]

## 💻 코드 패턴 (Code patterns)
Static variable persisting across function calls (PHP):
```php
function myTest() {
    static $x = 0;
    echo $x;
    $x++;
}
myTest(); // 0
myTest(); // 1
myTest(); // 2
```

## ✅ 검증 상태 및 신뢰도
- **상태:** draft
- **검증 단계:** conceptual
- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
- **신뢰 점수:** 0.90
- **중복 검사 결과:** 신규 생성 (New discovery)

## 🔗 지식 그래프 (Knowledge Graph)
- **상위/루트:** [[PHP Tutorial]]
- **관련 개념:** [[PHP Variables]], [[PHP Superglobals Globals]], [[PHP Echo Print]]
- **참조 맥락:** 변수 스코프 규칙 — $GLOBALS는 Superglobals 챕터에서 심화.

## 📚 출처 (Sources)
- [S1] W3Schools — PHP Variable Scope — https://www.w3schools.com/php/php_variables_scope.asp

## 📝 변경 이력 (Change history)
- 2026-07-04: Initial draft synthesized from the W3Schools "PHP Variable Scope" page (Astra wiki-curation, P-Reinforce v3.1 format).
