---
id: c-pointer-to-pointer
title: "C Pointer to Pointer"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["double pointer", "int**", "C 포인터의 포인터"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.86
created_at: 2026-07-04
updated_at: 2026-07-04
review_reason: ""
merge_history: []
tags: ["c", "programming-language", "w3schools", "pointers", "double-pointer"]
raw_sources: ["https://www.w3schools.com/c/c_pointer_to_pointer.php"]
applied_in: []
github_commit: ""
---

# [[C Pointer to Pointer]]

## 🎯 한 줄 통찰 (One-line insight)
The source's own analogy nails the concept exactly: "a normal pointer is like a note with an address on it; a pointer to pointer is like another note telling you where that first note is kept" — meaning `**pptr` isn't some special new operation, it's just applying the SAME dereference (`*`) operator TWICE in a row, following one address to find a second address, then following that to find the actual value. [S1]

## 🧠 핵심 개념 (Core concepts)
- **Pointer to pointer (double pointer, `int **pptr`)** — a pointer whose stored value is the ADDRESS OF ANOTHER POINTER, not a regular variable. [S1]
- **One extra level of indirection** — `*ptr` gives a variable's value directly; `**pptr` gives the same value by following TWO addresses in sequence (pptr → ptr → myNum). [S1]
- **Mutability through both levels** — assigning through `**pptr = 20;` changes the ORIGINAL variable (`myNum`), just as `*ptr = 20;` would. [S1]
- **Use cases** — passing pointers into functions (so the function can modify what a pointer points to) and working with complex/nested data structures. [S1]

## 📖 세부 내용 (Details)
- Declaring and reading through two levels: `int myNum = 10; int *ptr = &myNum; int **pptr = &ptr; printf("**pptr = %d\n", **pptr); // 10`. [S1]
- Modifying the original variable through the double pointer: `int myNum = 5; int *ptr = &myNum; int **pptr = &ptr; **pptr = 20; printf("myNum = %d\n", myNum); // 20`. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
- 현재까지 발견된 모순 사항 없음 (No contradictions found in available sources).

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — 함수에 포인터를 전달해 그 포인터 자체를 함수 안에서 바꿔야 할 때, 그리고 복잡한 자료구조를 다룰 때 포인터의 포인터가 유용하다고 원문에 명시됨. [S1]

## 💻 코드 패턴 (Code patterns)
Modifying the original variable through two levels of pointer indirection (C):
```c
int myNum = 5;
int *ptr = &myNum;
int **pptr = &ptr;
**pptr = 20; // changes myNum
printf("myNum = %d\n", myNum); // prints 20
```

## ✅ 검증 상태 및 신뢰도
- **상태:** draft
- **검증 단계:** conceptual
- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
- **신뢰 점수:** 0.86
- **중복 검사 결과:** 신규 생성 (New discovery)

## 🔗 지식 그래프 (Knowledge Graph)
- **상위/루트:** [[C Tutorial]]
- **관련 개념:** [[C Pointers Arrays]], [[C Memory Access]], [[C Functions Pointers]]
- **참조 맥락:** 포인터의 포인터 — 동적 메모리 접근(Memory Access) 챕터로 이어짐.

## 📚 출처 (Sources)
- [S1] W3Schools — C Pointer to Pointer — https://www.w3schools.com/c/c_pointer_to_pointer.php

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