ulimit(3p) — Linux manual page


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

PROLOG         top

       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         top

       ulimit — get and set process limits

SYNOPSIS         top

       #include <ulimit.h>

       long ulimit(int cmd, ...);

DESCRIPTION         top

       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

       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         top

       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         top

       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         top



       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         top



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

SEE ALSO         top

       exec(1p), getrlimit(3p), write(3p)

       The Base Definitions volume of POSIX.1‐2008, ulimit.h(0p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The Open
       Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
       applied.) 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.unix.org/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 .

IEEE/The Open Group                 2013                          ULIMIT(3P)

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