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

       ulimit — get and set process limits

SYNOPSIS

       #include <ulimit.h>

       long ulimit(int cmd, ...);

DESCRIPTION

       The  ulimit()  function  shall  control  process  limits.  The  process limits that can be
       controlled by this function include the maximum size of a single file that can be  written
       (this  is  equivalent  to using setrlimit() with RLIMIT_FSIZE). The cmd values, defined in
       <ulimit.h>, include:

       UL_GETFSIZE Return the file size limit (RLIMIT_FSIZE) of the process. The limit  shall  be
                   in  units  of 512-byte blocks and shall be inherited by child processes. Files
                   of any size can be read. The return value shall be the  integer  part  of  the
                   soft  file size limit divided by 512. If the result cannot be represented as a
                   long, the result is unspecified.

       UL_SETFSIZE Set the file size limit for output operations of the process to the  value  of
                   the  second  argument, taken as a long, multiplied by 512. If the result would
                   overflow an rlim_t, the actual value  set  is  unspecified.  Any  process  may
                   decrease  its  own  limit,  but only a process with appropriate privileges may
                   increase the limit. The return value shall be the integer part of the new file
                   size limit divided by 512.

       The ulimit() function shall not change the setting of errno if successful.

       As  all return values are permissible in a successful situation, an application wishing to
       check for error situations should set errno to 0, then call ulimit(), and, if  it  returns
       -1, check to see if errno is non-zero.

RETURN VALUE

       Upon  successful  completion,  ulimit()  shall  return  the  value of the requested limit.
       Otherwise, -1 shall be returned and errno set to indicate the error.

ERRORS

       The ulimit() function shall fail and the limit shall be unchanged if:

       EINVAL The cmd argument is not valid.

       EPERM  A process not having appropriate privileges attempts  to  increase  its  file  size
              limit.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       Since  the  ulimit()  function  uses  type  long  rather than rlim_t, this function is not
       sufficient  for  file  sizes  on  many  current  systems.   Applications  should  use  the
       getrlimit() or setrlimit() functions instead of the obsolescent ulimit() function.

RATIONALE

       None.

FUTURE DIRECTIONS

       The ulimit() function may be removed in a future version.

SEE ALSO

       exec, getrlimit(), write()

       The Base Definitions volume of POSIX.1‐2017, <ulimit.h>

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 .