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34 .Nd get/set program scheduling priority
41 .Fn getpriority "int which" "int who"
43 .Fn setpriority "int which" "int who" "int prio"
46 priority of the process, process group, or user, as indicated by
52 system call and set with the
65 is interpreted relative to
67 (a process identifier for
76 denotes the current process, process group, or user.
80 is a value in the range -20 to 20.
81 The default priority is 0;
82 lower priorities cause more favorable scheduling.
86 system call returns the highest priority (lowest numerical value)
87 enjoyed by any of the specified processes.
90 system call sets the priorities of all of the specified processes
91 to the specified value.
92 Only the super-user may lower priorities.
96 can legitimately return the value -1, it is necessary
97 to clear the external variable
100 call, then check it afterward to determine
101 if a -1 is an error or a legitimate value.
113 No process was located using the
129 In addition to the errors indicated above,
134 A process was located, but neither its effective nor real user
135 ID matched the effective user ID of the caller.
137 A non super-user attempted to lower a process priority.
146 system call appeared in