Cross-compiling is where you write code on one machine but build it for another machine that runs a different operating system or processor. For instance, you could be developing your application on Windows but build it for a Linux machine; or you could be writing the code on an x86 Linux machine but building the executable for an ARMv8 Linux device.
Cross-compilation is required in the following cases:
- The Qt toolchain or library is not available on the target device you're running
- The target device is really slow and not suitable for compiling the code
- The device doesn't have any display or input method
Qt commercial makes it really easy to cross-compile and deploy your application to different types of embedded devices, so a manual way is not recommended unless the hardware is not officially supported by Qt.
...