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



PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (con-
       sult 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
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       getrlimit(), setrlimit(), write(), the Base Definitions volume of IEEE Std 1003.1-2001, <ulimit.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003  Edition,  Standard  for
       Information  Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copy-
       right (C) 2001-2003 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.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                    ULIMIT(3P)