Make a C program use less CPU.

1. Keyloggers are definitely malicious.

2. Writing a program 'in the manner of a keylogger' is also by definition malicious. Why wouldn't you want your program to be discoverable/managable by the user? If you are looking to hide your program from users, you want to hide it for a reason.. and honestly I can't come up with a reason to hide a program from users that doesn't involve malicious intent.

This makes you someone wishing to write malicious software. You'll find little support for such things on this site. We are all professionals, some of us working on products that battle malicious programs.

There is no C code that you can add to a program to use less CPU. It will use as much CPU as required by the execution of the instructions in the program. Maybe you need to explain in better detail exactly what problem you are trying to solve, just as long as it's not about hacking.

The best way for you to make your application to use less CPU and resources is to use this really cool exit(); function. It works really well. You'll find that your application will sleep really well and use virtually no resources.

If you want it to use less CPU then write fewer instructions. If you want to run it in stealth mode then that suggests you are or wish to be a hacker: we do not support such people on this site.