strings.c:21:6: Function main declared to return void, should return int
strings.c: (in function main)
strings.c:24:14: Function call may modify observer: "hullo"
   strings.c:24:14: Storage becomes observer
strings.c:25:7: Observer storage passed as only param: f3 ("hullo")
   strings.c:25:7: Storage becomes observer

Finished checking --- 3 code warnings, as expected

strings.c:21:6: Function main declared to return void, should return int

Finished checking --- 1 code warning, as expected

strings.c: (in function main)
strings.c:23:14: Call to unconstrained function f1 may modify observer: "hullo"
   strings.c:23:14: Storage becomes observer
strings.c:24:14: Function call may modify observer: "hullo"
   strings.c:24:14: Storage becomes observer
strings.c:25:7: Call to unconstrained function f3 may modify observer: "hullo"
   strings.c:25:7: Storage becomes observer
strings.c:25:7: Observer storage passed as only param: f3 ("hullo")
   strings.c:25:7: Storage becomes observer

Finished checking --- 4 code warnings, as expected