If you used Visual Studio to write C++ or CUDA code, then you are familiar with using the Release and Debug build configurations. Having these two pre-defined configurations helps you write correct code first and then optimize it for speed to release it to your users.
Similar to that, Release and Debug build configurations are available for C++ and CUDA code in Eclipse CDT and NSight Eclipse Edition too. The only problem is that Eclipse hides this, so you are not even aware that this exists and which configuration you are currently working with.
To view or switch the current Build Configuration just go to Project > Build Configurations > Set Active
To change the compiler options and other settings that are used with a Build Configuration, right-click on the project name in Project Explorer and choose Properties > C/C++ Build. You can see the current configuration in the dropdown at the top and change it to a different one. All the settings under this section are part of the chosen Build Configuration.
Tried with: Eclipse 3.7.2, Eclipse CDT 8.0.2 and Ubuntu 12.04 LTS