About GPL and LGPL

Recently, I checked GPL and LGPL on the Internet and made some notes. Before that, the author of Building Embeded Linux System was quoted as follows:

The following is a legal disclaimer. We are not lawyers. If you have any questions about your plan, consult a lawyer.

In addition to GPL and LGPL, there are BSD and MPL, but GPL and LGPL are the most popular in Linux. Both GPL and LGPL are public License, which is used to restrict users and developer permissions for secondary development, that is, their rights and obligations, rather than declaring the provider's interests.

To put it simply, GPL is virus-spreading. You include GPL. Whether modified or not, you must also be GPL. LGPL is the content of your modified LGPL, you must also be LGPL.

GPL (GUN General Public License)

• The protected object is an application.

  : For example, Kernel, butil tools, gcc, and gdb.

• High degrees of freedom for developers and users

  So that they can use/modify/release software with almost no restrictions.

  • You can copy the program without changing the license and copyright notice.
  • GPL's license to the software does not include any warranty unless it is provided by the issuer. You may be charged for providing copy and guarantee services to others. (GPL and lgpl encourage free distribution of software, but it does not mean that GPL/lgpl software must be free of charge. For example, RedHat Linux Enterprise is a paid software, only paying users can get the software and distribute it to others for free. Therefore, most GPL/lgpl software manufacturers can only charge Software Value-added Service Fees)
  • The source code must be included in the binary copy of the release program, which usually refers to the "original" source code.
  • As long as you modify or include any part of the program or program protected by GPL, you must comply with GPL regulations. Otherwise, you cannot issue the program externally.
  • Package unmodified Software without the above restrictions.
• For the execution of GPL software:

  No need to worry about GPL, such as using the GCC compiler

• For

  Build derivative works based on original software

  • Follow GPL rules
  • Whether static or dynamic connections are used, private applications integrate GPL software through dynamic links during execution and will still be subject to GPL restrictions.
  • The Protocol diffusion scope of GPL software is limited to the process space, and the use of GPL software across processes is not subject to GPL
• Patent problems:

  Any patent must be made on the premise that everyone is allowed to use it freely. Otherwise, no patent is allowed. If you re-release the GPL software, you hereby authorize the recipient to use the patents contained in this GPL software.

LGPL (more loose GPL, that is, Lesser GPL)

• The protected object is the Linked Library:

  For example, glibc and GTK Widget Toolkit.

• For

  Build derivative works based on original software

  • Some unmodified LGPL programs are used in the program, so you do not need to consider the limitations of LGPL.
  • The modified LGPL must comply with the LGPL rules; otherwise, it cannot be released externally.
  • Which of the following is a dynamically or dynamically connected library included by LGPL? No restrictions are imposed and any license can be used to issue software. For the Replacement Problem of LGPL software, if the static link method is used, the software user must provide the target code of the application before the link. If the LGPL library is used, if the source code of the Import and Export library is compiled together, it should be open-source even if the library code is not modified. If the static link is used (including the header file of the Library), no source code should be published, but to release. o (obj) files, such as dynamic links, can be completely closed.
• Patent Problems
• A function library can obtain
  Any patents obtained must be consistent with the "completely free to use" stated in this license.

MPL (The Mozilla Public License)

•  Important Terms
  

  • Modifications to the source code published by the MPL license must also be made through the MPL license.
  • The definition of "publish" is "file published in source code", which means that MPL allows an enterprise to add an interface to its existing source code library, in addition to the MPL license, the source code in the source code library can be forcibly licensed without the MPL license.
  • Allow licensee to mix the source code obtained through the MPL license with other types of code to obtain their own software programs

• Patents
  • 
    The source code provider cannot provide the source code that has been protected by a patent (unless he is a patent holder and is required to allow the source code to the public for free ), you cannot apply for patents related to the source code after you license the source code in the form of an open source code license.

These licenses are legally protected in the United States. If they are violated in China, it is unclear whether there is a problem because it is unclear whether these licenses have legal effects in China. Domestic intellectual property laws seem to be lacking in protection of open-source protocols. There are many enterprises in China that violate the open-source protocols, but they are not subject to legal sanctions. It is said that only the author of open-source software could win the case if an enterprise violates the open-source protocol.
However, from the developer's point of view, GPL and LGPL oppose the monopoly or occupation of technology through patent charges. They provide open and open methods, they also require their users to follow this principle. This is the Communist term of the network, and we should follow them. green Dam was not very generous in this regard last year. There are a lot of research comments on the Internet.

 

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