[Qt5-feedback] Qt major versions

[marius.storm-olsen at nokia.com]

On 25/05/2011 08:21, ext Konstantin Tokarev wrote:
> 25.05.2011, 16:39, "Charley Bay" <charleyb123 at gmail.com>:
>> What about out-of-the-box support for static library linking?
>> While not perfect for every application, large desktop applications
>> like Maya could simply statically-link the required Qt version, and
>> never suffer the "anomalies" of system Qt library upgrade.
>>
>> I've built-and-statically-linked Qt, but IMHO it would be nice if
>> the static libs were a first-class deployment option (e.g.,
>> automatically available when Qt is installed, I'm a commercial
>> customer).
>>
>> Yes, LGPL applications would still need dynamic linking, so I
>> concede that doesn't address the problem from that standpoint.
>>
>> Anybody out there shipping with statically-linked Qt?
>
> Static linking is an ugly solution. While it goes when product is one
> executable file, it significantly bloats size when several binaries
> are built, and it truly sucks in case of "application + library +
> lots of plugins", because Qt is linked multiple times.
>
> Dynamic linking itself does not cause any troubles as long as you can
> ship all needed libraries with your product.

For applications which are paranoid about only using their own version 
of Qt, also for plugins etc; and want to distribute their own version 
whenever they've tested it; and which is also compatible with LGPL, you 
have the option to use an infixed Qt.

      configure -qtlibinfix maya

would then create QtCore_maya4.dll on Windows, and all your plugins 
could link to the same. That way they are unaffected by any other 
installed Qt and unrelated application installs/upgrades.

There's *always* a risk that something else breaks when you do a change 
to a library, although we try to keep BC as best as possible. Even if we 
added Minor version number to the library, a Patch release security 
update might still affect your application! If we add both Minor and 
Patch numbers to the libraries, then it would be exactly the same as 
using your own custom infix.

So, if the risks are unacceptable to you, then just use a custom Qt with 
your own infix, and accept the responsibility to upgrade Qt whenever 
required, and push those to your customers in a timely manner.

-- 
..marius