diff --git a/lib/posix/posix.nim b/lib/posix/posix.nim
index 8c82122982..a559367790 100644
--- a/lib/posix/posix.nim
+++ b/lib/posix/posix.nim
@@ -503,7 +503,7 @@ proc pthread_spin_unlock*(a1: ptr Pthread_spinlock): cint {.
 proc pthread_testcancel*() {.importc, header: "<pthread.h>".}
 
 
-proc exitnow*(code: int) {.importc: "_exit", header: "<unistd.h>".}
+proc exitnow*(code: cint) {.importc: "_exit", header: "<unistd.h>", noreturn.}
 proc access*(a1: cstring, a2: cint): cint {.importc, header: "<unistd.h>".}
 proc alarm*(a1: cint): cint {.importc, header: "<unistd.h>".}
 proc chdir*(a1: cstring): cint {.importc, header: "<unistd.h>".}