'\" et
.TH sys_resource.h "0P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\"
.SH 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.
.\"
.SH NAME
sys/resource.h
\(em definitions for XSI resource operations
.SH SYNOPSIS
.LP
.nf
#include <sys/resource.h>
.fi
.SH DESCRIPTION
The
.IR <sys/resource.h> 
header shall define the following symbolic constants as possible values
of the
.IR which
argument of
\fIgetpriority\fR()
and
\fIsetpriority\fR():
.IP PRIO_PROCESS 16
Identifies the
.IR who
argument as a process ID.
.IP PRIO_PGRP 16
Identifies the
.IR who
argument as a process group ID.
.IP PRIO_USER 16
Identifies the
.IR who
argument as a user ID.
.P
The
.IR <sys/resource.h> 
header shall define the following type through
.BR typedef :
.IP "\fBrlim_t\fR" 16
Unsigned integer type used for limit values.
.P
The
.IR <sys/resource.h> 
header shall define the following symbolic constants, which shall have
values suitable for use in
.BR #if
preprocessing directives:
.IP RLIM_INFINITY 16
A value of
.BR rlim_t
indicating no limit.
.IP RLIM_SAVED_MAX 16
A value of type
.BR rlim_t
indicating an unrepresentable saved hard limit.
.IP RLIM_SAVED_CUR 16
A value of type
.BR rlim_t
indicating an unrepresentable saved soft limit.
.P
On implementations where all resource limits are representable in an
object of type
.BR rlim_t ,
RLIM_SAVED_MAX and RLIM_SAVED_CUR need not be distinct from
RLIM_INFINITY.
.P
The
.IR <sys/resource.h> 
header shall define the following symbolic constants as possible values
of the
.IR who
parameter of
\fIgetrusage\fR():
.IP RUSAGE_SELF 16
Returns information about the current process.
.IP RUSAGE_CHILDREN 16
Returns information about children of the current process.
.P
The
.IR <sys/resource.h> 
header shall define the
.BR rlimit
structure, which shall include at least the following members:
.sp
.RS 4
.nf

rlim_t rlim_cur  \fRThe current (soft) limit.\fR
rlim_t rlim_max  \fRThe hard limit.\fR
.fi
.P
.RE
.P
The
.IR <sys/resource.h> 
header shall define the
.BR rusage
structure, which shall include at least the following members:
.sp
.RS 4
.nf

struct timeval ru_utime  \fRUser time used.\fR
struct timeval ru_stime  \fRSystem time used.\fR
.fi
.P
.RE
.P
The
.IR <sys/resource.h> 
header shall define the
.BR timeval
structure as described in
.IR <sys/time.h> .
.P
The
.IR <sys/resource.h> 
header shall define the following symbolic constants as possible values
for the
.IR resource
argument of
\fIgetrlimit\fR()
and
\fIsetrlimit\fR():
.IP RLIMIT_CORE 16
Limit on size of
.BR core
file.
.IP RLIMIT_CPU 16
Limit on CPU time per process.
.IP RLIMIT_DATA 16
Limit on data segment size.
.IP RLIMIT_FSIZE 16
Limit on file size.
.IP RLIMIT_NOFILE 16
Limit on number of open files.
.IP RLIMIT_STACK 16
Limit on stack size.
.IP RLIMIT_AS 16
Limit on address space size.
.P
The following shall be declared as functions and may also be defined as
macros. Function prototypes shall be provided.
.sp
.RS 4
.nf

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 *);
.fi
.P
.RE
.P
The
.IR <sys/resource.h> 
header shall define the
.BR id_t
type through
.BR typedef ,
as described in
.IR <sys/types.h> .
.P
Inclusion of the
.IR <sys/resource.h> 
header may also make visible all symbols from
.IR <sys/time.h> .
.LP
.IR "The following sections are informative."
.SH "APPLICATION USAGE"
None.
.SH RATIONALE
None.
.SH "FUTURE DIRECTIONS"
None.
.SH "SEE ALSO"
.IR "\fB<sys_time.h>\fP",
.IR "\fB<sys_types.h>\fP"
.P
The System Interfaces volume of POSIX.1\(hy2017,
.IR "\fIgetpriority\fR\^(\|)",
.IR "\fIgetrlimit\fR\^(\|)",
.IR "\fIgetrusage\fR\^(\|)"
.\"
.SH 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 .
.PP
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 .