GNU Lesser General Public License (LGPL) | Qt 5.15

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- GNU Lesser General Public License (LGPL)
- Qt 5.15.17 Reference Documentation

# GNU Lesser General Public License (LGPL)

Qt is available under the GNU Lesser General Public License version 3.

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- GNU Lesser General Public License, version 3

## LGPL version 3

                        GNU LESSER GENERAL PUBLIC LICENSE
                            Version 3, 29 June 2007

      Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
      Everyone is permitted to copy and distribute verbatim copies
      of this license document, but changing it is not allowed.

       This version of the GNU Lesser General Public License incorporates
     the terms and conditions of version 3 of the GNU General Public
     License, supplemented by the additional permissions listed below.

       0. Additional Definitions.

       As used herein, "this License" refers to version 3 of the GNU Lesser
     General Public License, and the "GNU GPL" refers to version 3 of the GNU
     General Public License.

       "The Library" refers to a covered work governed by this License,
     other than an Application or a Combined Work as defined below.

       An "Application" is any work that makes use of an interface provided
     by the Library, but which is not otherwise based on the Library.
     Defining a subclass of a class defined by the Library is deemed a mode
     of using an interface provided by the Library.

       A "Combined Work" is a work produced by combining or linking an
     Application with the Library.  The particular version of the Library
     with which the Combined Work was made is also called the "Linked
     Version".

       The "Minimal Corresponding Source" for a Combined Work means the
     Corresponding Source for the Combined Work, excluding any source code
     for portions of the Combined Work that, considered in isolation, are
     based on the Application, and not on the Linked Version.

       The "Corresponding Application Code" for a Combined Work means the
     object code and/or source code for the Application, including any data
     and utility programs needed for reproducing the Combined Work from the
     Application, but excluding the System Libraries of the Combined Work.

       1. Exception to Section 3 of the GNU GPL.

       You may convey a covered work under sections 3 and 4 of this License
     without being bound by section 3 of the GNU GPL.

       2. Conveying Modified Versions.

       If you modify a copy of the Library, and, in your modifications, a
     facility refers to a function or data to be supplied by an Application
     that uses the facility (other than as an argument passed when the
     facility is invoked), then you may convey a copy of the modified
     version:

        a) under this License, provided that you make a good faith effort to
        ensure that, in the event an Application does not supply the
        function or data, the facility still operates, and performs
        whatever part of its purpose remains meaningful, or

        b) under the GNU GPL, with none of the additional permissions of
        this License applicable to that copy.

       3. Object Code Incorporating Material from Library Header Files.

       The object code form of an Application may incorporate material from
     a header file that is part of the Library.  You may convey such object
     code under terms of your choice, provided that, if the incorporated
     material is not limited to numerical parameters, data structure
     layouts and accessors, or small macros, inline functions and templates
     (ten or fewer lines in length), you do both of the following:

        a) Give prominent notice with each copy of the object code that the
        Library is used in it and that the Library and its use are
        covered by this License.

        b) Accompany the object code with a copy of the GNU GPL and this license
        document.

       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.

        c) For a Combined Work that displays copyright notices during
        execution, include the copyright notice for the Library among
        these notices, as well as a reference directing the user to the
        copies of the GNU GPL and this license document.

        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.  A suitable mechanism is one that (a) uses at run time
            a copy of the Library already present on the user's computer
            system, and (b) will operate properly with a modified version
            of the Library that is interface-compatible with the Linked
            Version.

        e) Provide Installation Information, but only if you would otherwise
        be required to provide such information under section 6 of the
        GNU GPL, and only to the extent that such information is
        necessary to install and execute a modified version of the
        Combined Work produced by recombining or relinking the
        Application with a modified version of the Linked Version. (If
        you use option 4d0, the Installation Information must accompany
        the Minimal Corresponding Source and Corresponding Application
        Code. If you use option 4d1, you must provide the Installation
        Information in the manner specified by section 6 of the GNU GPL
        for conveying Corresponding Source.)

       5. Combined Libraries.

       You may place library facilities that are a work based on the
     Library side by side in a single library together with other library
     facilities that are not Applications and are not covered by this
     License, and convey such a combined library under terms of your
     choice, if you do both of the following:

        a) Accompany the combined library with a copy of the same work based
        on the Library, uncombined with any other library facilities,
        conveyed under the terms of this License.

        b) Give prominent notice with the combined library that part of it
        is a work based on the Library, and explaining where to find the
        accompanying uncombined form of the same work.

       6. Revised Versions of the GNU Lesser General Public License.

       The Free Software Foundation may publish revised and/or new versions
     of the GNU Lesser General Public License from time to time. Such new
     versions will be similar in spirit to the present version, but may
     differ in detail to address new problems or concerns.

       Each version is given a distinguishing version number. If the
     Library as you received it specifies that a certain numbered version
     of the GNU Lesser General Public License "or any later version"
     applies to it, you have the option of following the terms and
     conditions either of that published version or of any later version
     published by the Free Software Foundation. If the Library as you
     received it does not specify a version number of the GNU Lesser
     General Public License, you may choose any version of the GNU Lesser
     General Public License ever published by the Free Software Foundation.

       If the Library as you received it specifies that a proxy can decide
     whether future versions of the GNU Lesser General Public License shall
     apply, that proxy's public statement of acceptance of any version is
     permanent authorization for you to choose that version for the
     Library.