sys_resource.h
Section: POSIX Programmer's Manual (0P)
Updated: 2017
Page Index
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.
NAME
sys/resource.h
--- definitions for XSI resource operations
SYNOPSIS
#include <sys/resource.h>
DESCRIPTION
The
<sys/resource.h>
header shall define the following symbolic constants as possible values
of the
which
argument of
getpriority()
and
setpriority():
- PRIO_PROCESS
-
Identifies the
who
argument as a process ID.
- PRIO_PGRP
-
Identifies the
who
argument as a process group ID.
- PRIO_USER
-
Identifies the
who
argument as a user ID.
The
<sys/resource.h>
header shall define the following type through
typedef:
- rlim_t
-
Unsigned integer type used for limit values.
The
<sys/resource.h>
header shall define the following symbolic constants, which shall have
values suitable for use in
#if
preprocessing directives:
- RLIM_INFINITY
-
A value of
rlim_t
indicating no limit.
- RLIM_SAVED_MAX
-
A value of type
rlim_t
indicating an unrepresentable saved hard limit.
- RLIM_SAVED_CUR
-
A value of type
rlim_t
indicating an unrepresentable saved soft limit.
On implementations where all resource limits are representable in an
object of type
rlim_t,
RLIM_SAVED_MAX and RLIM_SAVED_CUR need not be distinct from
RLIM_INFINITY.
The
<sys/resource.h>
header shall define the following symbolic constants as possible values
of the
who
parameter of
getrusage():
- RUSAGE_SELF
-
Returns information about the current process.
- RUSAGE_CHILDREN
-
Returns information about children of the current process.
The
<sys/resource.h>
header shall define the
rlimit
structure, which shall include at least the following members:
-
rlim_t rlim_cur The current (soft) limit.
rlim_t rlim_max The hard limit.
The
<sys/resource.h>
header shall define the
rusage
structure, which shall include at least the following members:
-
struct timeval ru_utime User time used.
struct timeval ru_stime System time used.
The
<sys/resource.h>
header shall define the
timeval
structure as described in
<sys/time.h>.
The
<sys/resource.h>
header shall define the following symbolic constants as possible values
for the
resource
argument of
getrlimit()
and
setrlimit():
- RLIMIT_CORE
-
Limit on size of
core
file.
- RLIMIT_CPU
-
Limit on CPU time per process.
- RLIMIT_DATA
-
Limit on data segment size.
- RLIMIT_FSIZE
-
Limit on file size.
- RLIMIT_NOFILE
-
Limit on number of open files.
- RLIMIT_STACK
-
Limit on stack size.
- RLIMIT_AS
-
Limit on address space size.
The following shall be declared as functions and may also be defined as
macros. Function prototypes shall be provided.
-
int getpriority(int, id_t);
int getrlimit(int, struct rlimit *);
int getrusage(int, struct rusage *);
int setpriority(int, id_t, int);
int setrlimit(int, const struct rlimit *);
The
<sys/resource.h>
header shall define the
id_t
type through
typedef,
as described in
<sys/types.h>.
Inclusion of the
<sys/resource.h>
header may also make visible all symbols from
<sys/time.h>.
The following sections are informative.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
<sys_time.h>,
<sys_types.h>
The System Interfaces volume of POSIX.1-2017,
getpriority(),
getrlimit(),
getrusage()
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1-2017, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
In the event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
Any typographical or formatting errors that appear
in this page are most likely
to have been introduced during the conversion of the source files to
man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .