изменить приятную ценность процесса (change the nice value of a process)
Пролог (Prolog)
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
Имя (Name)
nice — change the nice value of a process
Синопсис (Synopsis)
#include <unistd.h>
int nice(int incr);
Описание (Description)
The nice() function shall add the value of incr to the nice value
of the calling process. A nice value of a process is a non-
negative number for which a more positive value shall result in
less favorable scheduling.
A maximum nice value of 2*{NZERO}-1 and a minimum nice value of 0
shall be imposed by the system. Requests for values above or
below these limits shall result in the nice value being set to
the corresponding limit. Only a process with appropriate
privileges can lower the nice value.
Calling the nice() function has no effect on the priority of
processes or threads with policy SCHED_FIFO or SCHED_RR. The
effect on processes or threads with other scheduling policies is
implementation-defined.
The nice value set with nice() shall be applied to the process.
If the process is multi-threaded, the nice value shall affect all
system scope threads in the process.
As -1 is a permissible return value in a successful situation, an
application wishing to check for error situations should set
errno to 0, then call nice(), and if it returns -1, check to see
whether errno is non-zero.
Возвращаемое значение (Return value)
Upon successful completion, nice() shall return the new nice
value -{NZERO}. Otherwise, -1 shall be returned, the nice value
of the process shall not be changed, and errno shall be set to
indicate the error.
Ошибки (Error)
The nice() function shall fail if:
EPERM The incr argument is negative and the calling process does
not have appropriate privileges.
The following sections are informative.
Примеры (Examples)
Changing the Nice Value
The following example adds the value of the incr argument, -20,
to the nice value of the calling process.
#include <unistd.h>
...
int incr = -20;
int ret;
ret = nice(incr);
Использование в приложениях (Application usage)
None.
Обоснование (Rationale)
None.
Будущие направления (Future directions)
None.
Смотри также (See also)
exec(1p), getpriority(3p)
The Base Definitions volume of POSIX.1‐2017, limits.h(0p),
unistd.h(0p)
