sys_resource.h man page

Prolog

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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.

See Also

<sys_time.h>, <sys_types.h>

The System Interfaces volume of POSIX.1‐2008, getpriority(), getrlimit(), getrusage()

Info

2013 IEEE/The Open Group POSIX Programmer's Manual