Well.. i do not believe that.
I believe it is turtles all the way down.
Quote Originally Posted by kleinstein View Post
if you look at the plugin folder of the binary version, then you can see there is a postgresql driver as already compiled dll.
This is Qt software and does not include any part of the PostgreSQL source. It was built to dynamically link against any Postgresql client library > 7.3.
That means, some version of postgresql is used for this binary build.
Yes, but it does not mean the Postgresql is built into the plugin or the Qt libraries, which is what you asked ("How can i find out which version is compiled into it? ")
And that can also mean that some openssl version can also be used for building this postgresql version for ssl support...
Yes, but once again OpenSSL is not built into the Qt binaries the project distributes (also for legal reasons).
The relevant parts of the Qt 4 binaries were built to dynamically load and use OpenSSL libraries >= 0.9.7 if present but you best avoid those with Heartbleed vulnerability.
From Qt 5.2 the minimum version is 1.0.0 (See http://qt-project.org/doc/qt-5/build-sources.html)

The support of Postgresql connections over SSL requires that the Postgresql client library you chose to use is built with that support. This is independent of Qt's SSL support through QSslSocket etc.