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 .