Purpose of while(1); statement in C

Question

What purpose does while(1); serve ? I am aware while(1) (no semicolon) loops infinitely and is similar to a spinlock situation. However I do not

Answer 1

Please note that all valid statements of the language do not have to serve a purpose. They are valid per the grammar of the language. One can build many similar "useless" statements, such as if (1);. I see such statements as the conjunction of a conditional (if, while, etc.) and the empty statement ; (which is also a valid statement although it obviously serves no specific purpose).

That being said, I encountered while (1); in security code. When the user does something very bad with an embedded device, it can be good to block them from trying anything else. With while (1);, we can unconditionally block a device until an accredited operator manually reboots it.

while(1); can also be part of the implementation of a kernel panic, although a for(;;) {} loop seems to be a more common way of expressing the infinite loop, and there might be a non-empty body (for instance to panic_blink()).