libc-top-half/musl/src/unistd/nice.c

   1 #include <unistd.h>
   2 #include <errno.h>
   3 #include <sys/resource.h>
   4 #include <limits.h>
   5 #include "syscall.h"
   6
   7 int nice(int inc)
   8 {
   9         int prio = inc;
  10         // Only query old priority if it can affect the result.
  11         // This also avoids issues with integer overflow.
  12         if (inc > -2*NZERO && inc < 2*NZERO)
  13                 prio += getpriority(PRIO_PROCESS, 0);
  14         if (prio > NZERO-1) prio = NZERO-1;
  15         if (prio < -NZERO) prio = -NZERO;
  16         if (setpriority(PRIO_PROCESS, 0, prio)) {
  17                 if (errno == EACCES)
  18                         errno = EPERM;
  19                 return -1;
  20         } else {
  21                 return prio;
  22         }
  23 }