I need to maintain and develop largely C++ software to support a technical solution for multi user application testing. I want to use Ubuntu as the development platform and distribute my developed s/ware on all UNIX type and Windows systems.

The UI is fairly simple with menu options and displaying graphical results but the internal code is by far the main aspect. It needs to be tuned for performance and after 20 years of C development is extensive.

Can anyone suggest a suitable IDE to meet the need? Many tx for any input.