NAME

sys/resource.h — definitions for resource operations

SYNOPSIS

#include <sys/resource.h>

DESCRIPTION

^[XSI] 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.

^[XSI] 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.

^[XSI] 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 image.

RLIMIT_CPU

^[XSI] 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.

[XSI]
int  getpriority(int, id_t);

int  getrlimit(int, struct rlimit *);
[XSI]
int  getrusage(int, struct rusage *);
int  setpriority(int, id_t, int);

int  setrlimit(int, const struct rlimit *);

^[XSI] 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>.

APPLICATION USAGE

None.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

<sys/time.h>, <sys/types.h>

XSH getpriority, getrlimit, getrusage

CHANGE HISTORY

First released in Issue 4, Version 2.

Issue 5

Large File System extensions are added.

Issue 7

This reference page is clarified with respect to macros and symbolic constants.

Issue 8

Austin Group Defects 51 and 1669 are applied, moving the getrlimit() and setrlimit() functions, excluding the RLIMIT_CPU limit, from the XSI option to the Base.

Austin Group Defect 1141 is applied, changing the description of RLIMIT_CORE.