My program suddenly seems to stop executing but it does not crash, the process is still alive. What is wrong?

This may happen if your executable binary file is deleted while the program is running. For example, if you recompile your program the previous copy of the executable file is deleted, which can cause running instances of the program to freeze in this way. The recommended solution is that if you need to recompile while the program is running, create a copy of the executable file and execute the copy. Then, the original executable file can be safely deleted. Alternatively, rename the currently executing file to something new and unique (using the mv command) before recompiling/reinstalling your program.