GPLLGPL

GPLLGPL is not a single license but a reference to the GNU General Public License (GPL) and the GNU Lesser General Public License (LGPL) and the ways they interact in software licensing. Both licenses are published by the Free Software Foundation and share the goal of ensuring freedom to use, modify, and distribute software, while imposing copyleft requirements that affect derivative works. The GPL is a strong copyleft license, meaning that any derivative work based on GPL-licensed code must be released under the GPL when distributed. The LGPL, by contrast, adopts a weaker copyleft for libraries, allowing linking from non-GPL programs without requiring the entire combined work to be licensed under the GPL, provided certain conditions are met.

Key differences center on scope and obligations. The GPL applies to the whole work that constitutes a derivative of GPL-licensed code, requiring source distribution and preservation of license terms for the complete program. The LGPL is designed for libraries; it permits both dynamic and, in some cases, static linking with non-GPL software, but obligates that modifications to the LGPL-covered library be released under the LGPL and that users be able to replace the library with a modified version. When using LGPL libraries in proprietary software, distributors must provide access to the library’s source or offer to supply it, and must maintain notices and licensing terms for the library.

Practical implications include compatibility considerations and distribution choices. Developers choose GPL for stronger copyleft guarantees, or LGPL when they want broader use of a library, including in non-GPL software, while still maintaining a route for library improvements to be shared with the community.