---
id: php-superglobals-globals
title: "PHP Superglobals Globals"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["$GLOBALS", "PHP 글로벌 변수"]
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", "superglobals", "globals"]
raw_sources: ["https://www.w3schools.com/php/php_superglobals_globals.asp"]
applied_in: []
github_commit: ""
---

# [[PHP Superglobals Globals]]

## 🎯 한 줄 통찰 (One-line insight)
PHP is unusual among languages in that referencing a global variable by its bare name inside a function returns NOTHING (or errors) — you must explicitly use `$GLOBALS['x']` or the `global` keyword, unlike many languages where outer-scope variables are automatically visible inside nested functions. [S1]

## 🧠 핵심 개념 (Core concepts)
- **`$GLOBALS`** — an array containing references to all global variables. [S1]
- **Outermost-scope variables are global automatically** — but NOT automatically accessible inside functions. [S1]
- **Two ways to access a global inside a function** — `$GLOBALS['x']` or the `global $x;` declaration. [S1]
- **Bare name access fails** — `echo $x;` inside a function (without global/`$GLOBALS`) does not see the outer `$x`. [S1]
- **Creating a global from inside a function** — assigning to `$GLOBALS['z']` inside a function makes `$z` accessible outside it too. [S1]

## 📖 세부 내용 (Details)
- Access via $GLOBALS: `$x = 75; function myfunction() { echo $GLOBALS['x']; } myfunction(); // 75`. [S1]
- Bare name fails: `$x = 75; function myfunction() { echo $x; } myfunction(); // nothing/error`. [S1]
- Access via global keyword: `$x = 75; function myfunction() { global $x; echo $x; } myfunction(); // 75`. [S1]
- Creating a global from inside a function: `function result() { $GLOBALS['z'] = $GLOBALS['x'] + $GLOBALS['y']; } result(); echo $z;`. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
- **다른 언어와의 차이**: PHP는 함수 내부에서 전역 변수를 특별한 구문 없이 자동으로 사용할 수 없다는 점이 다른 프로그래밍 언어와 명확히 대비됨. [S1]

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — 함수 내부에서 $GLOBALS로 새 전역 변수를 생성하고 함수 밖에서 사용하는 패턴이 실전 활용의 대표 사례다. [S1]

## 💻 코드 패턴 (Code patterns)
Creating a global variable from inside a function via $GLOBALS (PHP):
```php
$x = 10;
$y = 20;
function result() {
    $GLOBALS['z'] = $GLOBALS['x'] + $GLOBALS['y'];
}
result();
echo $z; // 30
```

## ✅ 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 Scope]], [[PHP Superglobals Server]]
- **참조 맥락:** 변수 스코프의 $GLOBALS 심화 — 서버 정보($_SERVER) 챕터로 이어짐.

## 📚 출처 (Sources)
- [S1] W3Schools — PHP $GLOBALS Superglobal — https://www.w3schools.com/php/php_superglobals_globals.asp

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