1 #include <u.h> 2 #include <libc.h> 3 4 long 5 readn(int f, void *av, long n) 6 { 7 char *a; 8 long m, t; 9 10 a = av; 11 t = 0; 12 while(t < n){ 13 m = read(f, a+t, n-t); 14 if(m <= 0){ 15 if(t == 0) 16 return m; 17 break; 18 } 19 t += m; 20 } 21 return t; 22 } 23