I want develop a gratis software use Qt,I read the LPGL. I want by 4d1.But must provide the Installation Information in the manner specified by section 6 of the GNU GPL for conveying Corresponding Source. If by GNU GPL 6, must provide All Source Code.
Just dynamically link to Qt. If you dynamically link to LGPL libraries, there's nothing to worry about. @Cornstalks
But Qt LGPL say that:
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.
The 4d1:
- 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.
And The GNU GPL
The section 6's mean is Provide All Source Code.
LGPL 4e says
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.
Section 6 defines "installation information" as follows:
“Installation Information” for a User Product means any methods, procedures, authorization keys, or other information required to install and execute modified versions of a covered work in that User Product from a modified version of its Corresponding Source. The information must suffice to ensure that the continued functioning of the modified object code is in no case prevented or interfered with solely because modification has been made.
Which, in the case of an LGPL library, boils down to telling people how to replace the Qt DLLs with other ones.