I have an application that works fine in DEBUG mode under both Windows and Linux. The development tools are Qt Creator and MSVC under Windows, and Qt Creator and Eclipse under Linux.

Consistent with both platforms, in RELEASE mode only, several signals are not being received by their corresponding slots. I have diagnostic code in both DEBUG and RELEASE modes that will indicate if the connection call fails, will indicate when the signal is generated, and when the slot receives the signal. From what I observe, the connection is successful, the signal gets generated, but no slot is called as a result.

I have no warning messages from Qt during DEBUG mode.

I have performed rebuilds, deleted the binaries, re-ran qmake, clean, etc. with the same behavior. Again, no problems with the DEBUG mode, just RELEASE.

Does anyone have any idea of why the RELEASE mode libraries might have a problem that is not true with the DEBUG ones?

Is there a good signal/slot spy tool available or recommended that will support release mode debugging?

I looked at a Qt App called Conan, which may be of benefit for signal/spy diagnostics.

I am using Qt version 4.7.2, Open Source version