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- GETPRIORITY C Library Procedures GETPRIORITY
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- NNAAMMEE
- getpriority, setpriority - get/set program scheduling prior-
- ity
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- SSYYNNOOPPSSIISS
- ##iinncclluuddee <<ssyyss//rreessoouurrccee..hh>>
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- pprriioo == ggeettpprriioorriittyy((wwhhiicchh,, wwhhoo))
- iinntt pprriioo,, wwhhiicchh,, wwhhoo;;
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- sseettpprriioorriittyy((wwhhiicchh,, wwhhoo,, pprriioo))
- iinntt wwhhiicchh,, wwhhoo,, pprriioo;;
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- DDEESSCCRRIIPPTTIIOONN
- The scheduling priority of the process, process group, or
- user, as indicated by _w_h_i_c_h and _w_h_o is obtained with the
- _g_e_t_p_r_i_o_r_i_t_y call and set with the _s_e_t_p_r_i_o_r_i_t_y call. _W_h_i_c_h
- is one of PRIO_PROCESS, PRIO_PGRP, or PRIO_USER, and _w_h_o is
- interpreted relative to _w_h_i_c_h (a process identifier for
- PRIO_PROCESS, process group identifier for PRIO_PGRP, and a
- user ID for PRIO_USER). A zero value of _w_h_o denotes the
- current process, process group, or user. _P_r_i_o is a value in
- the range -20 to 20. The default priority is 0; lower
- priorities cause more favorable scheduling.
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- The _g_e_t_p_r_i_o_r_i_t_y call returns the highest priority (lowest
- numerical value) enjoyed by any of the specified processes.
- The _s_e_t_p_r_i_o_r_i_t_y call sets the priorities of all of the
- specified processes to the specified value. Only the
- super-user may lower priorities.
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- RREETTUURRNN VVAALLUUEE
- Since _g_e_t_p_r_i_o_r_i_t_y can legitimately return the value -1, it
- is necessary to clear the external variable _e_r_r_n_o prior to
- the call, then check it afterward to determine if a -1 is an
- error or a legitimate value. The _s_e_t_p_r_i_o_r_i_t_y call returns 0
- if there is no error, or -1 if there is.
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- EERRRROORRSS
- _G_e_t_p_r_i_o_r_i_t_y and _s_e_t_p_r_i_o_r_i_t_y may return one of the following
- errors:
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- [ESRCH] No process was located using the _w_h_i_c_h and
- _w_h_o values specified.
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- [EINVAL] _W_h_i_c_h was not one of PRIO_PROCESS, PRIO_PGRP,
- or PRIO_USER.
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- In addition to the errors indicated above, _s_e_t_p_r_i_o_r_i_t_y may
- fail with one of the following errors returned:
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- [EPERM] A process was located, but neither its
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- Sprite v1.0 May 22, 1986 1
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- GETPRIORITY C Library Procedures GETPRIORITY
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- effective nor real user ID matched the effec-
- tive user ID of the caller.
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- [EACCES] A non super-user attempted to lower a process
- priority.
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- SSEEEE AALLSSOO
- nice(1), fork(2), renice(8)
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- Sprite v1.0 May 22, 1986 2
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