lib/posix/priority.c

   1 /*
   2 priority.c
   3 */
   4
   5 #include <errno.h>
   6 #include <sys/types.h>
   7 #include <sys/resource.h>
   8 #include <lib.h>
   9 #include <unistd.h>
  10 #include <string.h>
  11 #include <stddef.h>
  12
  13
  14 int getpriority(int which, int who)
  15 {
  16         int v;
  17         message m;
  18
  19         m.m1_i1 = which;
  20         m.m1_i2 = who;
  21
  22         /* GETPRIORITY returns negative for error.
  23          * Otherwise, it returns the priority plus the minimum
  24          * priority, to distiginuish from error. We have to
  25          * correct for this. (The user program has to check errno
  26          * to see if something really went wrong.)
  27          */
  28
  29         if((v = _syscall(MM, GETPRIORITY, &m)) < 0) {
  30                 return v;
  31         }
  32
  33         return v + PRIO_MIN;
  34 }
  35
  36 int setpriority(int which, int who, int prio)
  37 {
  38         message m;
  39
  40         m.m1_i1 = which;
  41         m.m1_i2 = who;
  42         m.m1_i3 = prio;
  43
  44         return _syscall(MM, SETPRIORITY, &m);
  45 }
  46