LGPL v2.1 · v3
LGPL — 동적 링크 · 교체 가능하게 쓰면 앱 소스 비공개 가능, 고지 · 역공학 허용 조건
주의할 것
- 1앱이 LGPL 라이브러리를 쓴다는 사실과 LGPL 적용을 눈에 띄게 알리고 라이선스 사본(v3 는 GPL 사본도)을 함께 준다. 라이브러리를 고쳤으면 그 부분 소스는 공개해야 한다.
- 2이용자가 라이브러리를 수정본으로 바꿔 끼울 수 있어야 한다 — 공유 라이브러리(동적 링크)로 쓰거나, 정적 링크면 앱 오브젝트 파일을 제공해 재링크를 허용해야 한다(FAQ #LGPLStaticVsDynamic). iOS 처럼 교체가 사실상 막힌 환경은 위험하다.
- 3앱 이용약관(EULA)이 「수정 · 역공학 금지」를 포함하면 LGPL 과 충돌한다 — 라이브러리 수정과 그 디버깅을 위한 역공학은 허용해야 한다(v2.1 6조 · v3 4조).
실제 사례 0
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확인하지 못한 것
- iOS 앱스토어 배포 앱에서 LGPL 라이브러리 교체 가능성(4(d)) 을 충족할 수 있는지에 대한 FSF 공식 답변은 찾지 못했다 — 앱 내 동적 프레임워크 사용이 충분한지 논쟁이 있다.
- LGPLv3 3조는 헤더 파일에서 가져온 것이 「숫자 매개변수 · 자료구조 · 10줄 이하 매크로 · 인라인 함수 · 템플릿」 이면 고지 의무를 면제한다 — C++ 템플릿 라이브러리를 많이 쓰는 경우 이 조건을 따로 봐야 한다.
- LGPL 위반으로 한국에서 실제 분쟁이 된 사례는 찾지 못했다.
근거 5 · 2026. 11. 1. 확인
- 약관원문 확인Free Software FoundationGNU LGPL v2.1 — Section 6(결합 저작물 배포 조건)
As an exception to the Sections above, you may also combine or link a "work that uses the Library" with the Library to produce a work containing portions of the Library, and distribute that work under terms of your choice, provided that the terms permit modification of the work for the customer's own use and reverse engineering for debugging such modifications. You must give prominent notice with each copy of the work that the Library is used in it and that the Library and its use are covered by this License. You must supply a copy of this License.— Section 6 첫 · 둘째 단락
- 원문 갱신
- 1999. 2. 1.
- 확인한 날
- 2026. 11. 1.
- 약관원문 확인Free Software FoundationGNU LGPL v2.1 — Section 6(b) 공유 라이브러리 방식
b) Use a suitable shared library mechanism for linking with the Library. A suitable mechanism is one that (1) uses at run time a copy of the library already present on the user's computer system, rather than copying library functions into the executable, and (2) will operate properly with a modified version of the library, if the user installs one, as long as the modified version is interface-compatible with the version that the work was made with.— Section 6(b)
- 원문 갱신
- 1999. 2. 1.
- 확인한 날
- 2026. 11. 1.
- 약관원문 확인Free Software FoundationGNU LGPL v3 — 4. Combined Works
You may convey a Combined Work under terms of your choice that, taken together, effectively do not restrict modification of the portions of the Library contained in the Combined Work and reverse engineering for debugging such modifications, if you also do each of the following: a) Give prominent notice with each copy of the Combined Work that the Library is used in it and that the Library and its use are covered by this License. b) Accompany the Combined Work with a copy of the GNU GPL and this license document.— Section 4 서두 · (a) · (b)
- 원문 갱신
- 2007. 6. 29.
- 확인한 날
- 2026. 11. 1.
- 약관원문 확인Free Software FoundationGNU LGPL v3 — 4(d) 재링크 · 공유 라이브러리 조건
d) Do one of the following: 0) Convey the Minimal Corresponding Source under the terms of this License, and the Corresponding Application Code in a form suitable for, and under terms that permit, the user to recombine or relink the Application with a modified version of the Linked Version to produce a modified Combined Work, in the manner specified by section 6 of the GNU GPL for conveying Corresponding Source. 1) Use a suitable shared library mechanism for linking with the Library.— Section 4(d)
- 원문 갱신
- 2007. 6. 29.
- 확인한 날
- 2026. 11. 1.
- 공식 FAQ원문 확인Free Software FoundationFrequently Asked Questions about the GNU Licenses — #LGPLStaticVsDynamic
(1) If you statically link against an LGPLed library, you must also provide your application in an object (not necessarily source) format, so that a user has the opportunity to modify the library and relink the application. (2) If you dynamically link against an LGPLed library already present on the user's computer, you need not convey the library's source. On the other hand, if you yourself convey the executable LGPLed library along with your application, whether linked with statically or dynamically, you must also convey the library's sources, in one of the ways for which the LGPL provides.— #LGPLStaticVsDynamic
- 원문 갱신
- 2026. 1. 13.
- 확인한 날
- 2026. 11. 1.