how does Qt knows Qt-dll path in windows

hi
I am using windows-xp. i have installed Qt in the E directory.When i create Qt programs and try to run it by double clicking ,i get errors stating that QtGui dlls are not found.After setting the path to Qt-dlls directory and running the program in command prompt works fine.

But if i double click qt-assistant it gets executed without complaining about dlls.How does the assistant knows the dll path.i have checked the path environment variable,there is no information about qt dll's in it.

How does the assistant knows qt-dlls path

Have you added a path to your Qt's bin (smth like E:\Qt\4.4.3\bin) to the the environment variable PATH?

No. Thats my question
How does Qt-assistant is able to detect the dlls with out specifying the path in PATH env.

QtAssistant finds these dlls because these dlls and QtAssistant itself are located in the same directory.

Good Catch,
i should have noticed it.
Is there a mechanism without specifying the path the application should be able to find the dlls .Similar to rpath in unix-like systems

The only alternative is to place the DLLs in a system-wide directory, like C:\Windows\System32

Thanks
If i run a program from Qt Creator i dont need to place the dlls in system-wide directories or in the program's directory.

How does this work.

It probably modifies the system path (hence the directory becomes "system-wide").