1ULIMIT(3P)                 POSIX Programmer's Manual                ULIMIT(3P)
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PROLOG

6       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
7       implementation of this interface may differ (consult the  corresponding
8       Linux  manual page for details of Linux behavior), or the interface may
9       not be implemented on Linux.
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NAME

12       ulimit - get and set process limits
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SYNOPSIS

15       #include <ulimit.h>
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17       long ulimit(int cmd, ...);
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DESCRIPTION

21       The ulimit() function shall control process limits. The process  limits
22       that  can  be controlled by this function include the maximum size of a
23       single file that can be written (this  is  equivalent  to  using  setr‐
24       limit()  with  RLIMIT_FSIZE).  The  cmd  values, defined in <ulimit.h>,
25       include:
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27       UL_GETFSIZE
28              Return the file size limit (RLIMIT_FSIZE) of  the  process.  The
29              limit  shall  be in units of 512-byte blocks and shall be inher‐
30              ited by child processes. Files of any  size  can  be  read.  The
31              return  value  shall  be  the integer part of the soft file size
32              limit divided by 512. If the result cannot be represented  as  a
33              long, the result is unspecified.
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35       UL_SETFSIZE
36              Set  the file size limit for output operations of the process to
37              the value of the second argument, taken as a long, multiplied by
38              512.  If  the  result would overflow an rlim_t, the actual value
39              set is unspecified. Any process may decrease its own limit,  but
40              only  a  process  with  appropriate  privileges may increase the
41              limit. The return value shall be the integer  part  of  the  new
42              file size limit divided by 512.
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45       The ulimit() function shall not change the setting of errno if success‐
46       ful.
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48       As all return values are permissible  in  a  successful  situation,  an
49       application  wishing  to check for error situations should set errno to
50       0, then call ulimit(), and, if it returns -1, check to see if errno  is
51       non-zero.
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RETURN VALUE

54       Upon  successful  completion,  ulimit()  shall  return the value of the
55       requested limit. Otherwise, -1 shall be returned and errno set to indi‐
56       cate the error.
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ERRORS

59       The ulimit() function shall fail and the limit shall be unchanged if:
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61       EINVAL The cmd argument is not valid.
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63       EPERM  A process not having appropriate privileges attempts to increase
64              its file size limit.
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67       The following sections are informative.
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EXAMPLES

70       None.
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APPLICATION USAGE

73       None.
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RATIONALE

76       None.
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FUTURE DIRECTIONS

79       None.
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SEE ALSO

82       getrlimit(), setrlimit(),  write(),  the  Base  Definitions  volume  of
83       IEEE Std 1003.1-2001, <ulimit.h>
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86       Portions  of  this text are reprinted and reproduced in electronic form
87       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
88       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
89       Specifications Issue 6, Copyright (C) 2001-2003  by  the  Institute  of
90       Electrical  and  Electronics  Engineers, Inc and The Open Group. In the
91       event of any discrepancy between this version and the original IEEE and
92       The  Open Group Standard, the original IEEE and The Open Group Standard
93       is the referee document. The original Standard can be  obtained  online
94       at http://www.opengroup.org/unix/online.html .
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98IEEE/The Open Group                  2003                           ULIMIT(3P)
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