          = 0   // { int fork(void); }  SYS_READ          = 0   // { ssize_t read(int fd, void *buf, size_t nbyte); }  SYS_WRITE         = 0   // { ssize_t write(int fd, const void *buf, size_t nbyte); }  SYS_OPEN          = 0   // { int open(char *path, int flags, int mode); }  SYS_CLOSE         = 0   // { int close(int fd); }  SYS_WAIT0         = 0   // { int wait0(int pid, int *status, int options, struct rusage *rusage); } 