sys_resource.h(7POSIX)

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 .