[Development] Explicit linking vs dlopen/dlsym

Thiago Macieira thiago.macieira at intel.com
Sun Nov 23 23:57:10 CET 2014

On Sunday 23 November 2014 19:55:53 Allan Sandfeld Jensen wrote:
> The difference is with dlopen we can support more than one major version
> with the same binary making it possible to upgrade udev for instance
> without having to upgrade all of Qt at the same time. In this case it
> doesn't matter that much, but dlopen can allow for more painless upgrading
> for a rolling distro. 

Again, that's a situation that doesn't happen. The distribution knows when it 
will rev a library to a new major version and it knows how long it will keep 
the older version around for compatibility. In-between those two dates, the Qt 
libraries get rebuilt and everyone is happy.

> Imagine if libGL wasn't dlopen'ed, we don't want to
> update Qt binaries every time somebody updates their graphics driver.

I don't see the issue with graphics drivers. And we don't dlopen libGL either, 
we link to it, which is a source of problems by itself since we can't choose 
at runtime to use GL or GL ES2.

Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center

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