#define PID_ERROR ((pid_t) -1)
typedef int mapid_t;
-#define MAPID_ERROR ((mapid_t) -1)
+#define MAP_FAILED ((mapid_t) -1)
void halt (void) NO_RETURN;
void exit (int status) NO_RETURN;
pid_t exec (const char *file);
-int join (pid_t);
+int wait (pid_t);
bool create (const char *file, unsigned initial_size);
bool remove (const char *file);
int open (const char *file);
unsigned tell (int fd);
void close (int fd);
mapid_t mmap (int fd, void *addr);
-bool munmap (mapid_t);
+void munmap (mapid_t);
bool chdir (const char *dir);
bool mkdir (const char *dir);
void lsdir (void);