Timer in simple C

A modul which can timing a predefined time. After the timer is fired, the modul call a callback function to signaling the end of timing. - Timer resolution is choosable as ms, sec, min, or hour - Let a client register a new timer event with the selected resolution and value and callback function. (It can be placed a linked list) - Let the client set cycled parameter to cyclic repeating. - Let the existing event restartable (suggestion: assign an unique identifier to an event, client can reference an event by this identifier) - Let the clients can cancel a stated timer [login to view URL] My work using arrays. I need linked list.