To be extra pedantic, that's not what volatile does. Volatile ensures that access through the variable must behave strictly according to the rules of the C abstract machine, but the definition of access is implementation defined. A compiler author could define "access" to be "reads from the variable" or "writes to the variable", or neither, and make the entire keyword useless. As long as they document that somewhere, it's compliant with the standard. You think it means "reads and writes" but it doesn't have to.
It's tempting to write a "malicious compliance C compiler" that complies with the standard but makes all the most perverse possible choices.
Your comment is technically correct, but the original description of “volatile” in the parent comment is much clearer. It may be fun to imagine what would happen if the compiler writer were malicious, but it doesn’t really help us understand C.
Just like C compilers assume that the program is correct, the writers of the C standard assume that the people reading it are not insane or malicious.
> A compiler author could define "access" to be "reads from the variable" or "writes to the variable", or neither, and make the entire keyword useless. As long as they document that somewhere, it's compliant with the standard.
Nobody is going to accept that as a compliant implementation.
It's tempting to write a "malicious compliance C compiler" that complies with the standard but makes all the most perverse possible choices.