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



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

NNAAMMEE
       ulimit -- get and set process limits

SSYYNNOOPPSSIISS
       #include <ulimit.h>

       long ulimit(int _c_m_d, ...);

DDEESSCCRRIIPPTTIIOONN
       The _u_l_i_m_i_t() 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
       _s_e_t_r_l_i_m_i_t() with RLIMIT_FSIZE). The _c_m_d values, defined in _<_u_l_i_m_i_t_._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 lloonngg, 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
                   lloonngg, multiplied by 512. If the result would overflow an
                   rrlliimm__tt, 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 _u_l_i_m_i_t() function shall not change the setting of _e_r_r_n_o if
       successful.

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

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

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

       EEIINNVVAALL The _c_m_d argument is not valid.

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

       _T_h_e _f_o_l_l_o_w_i_n_g _s_e_c_t_i_o_n_s _a_r_e _i_n_f_o_r_m_a_t_i_v_e_.

EEXXAAMMPPLLEESS
       None.

AAPPPPLLIICCAATTIIOONN UUSSAAGGEE
       Since the _u_l_i_m_i_t() function uses type lloonngg rather than rrlliimm__tt, this
       function is not sufficient for file sizes on many current systems.
       Applications should use the _g_e_t_r_l_i_m_i_t() or _s_e_t_r_l_i_m_i_t() functions
       instead of the obsolescent _u_l_i_m_i_t() function.

RRAATTIIOONNAALLEE
       None.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       The _u_l_i_m_i_t() function may be removed in a future version.

SSEEEE AALLSSOO
       _e_x_e_c, _g_e_t_r_l_i_m_i_t(), _w_r_i_t_e()

       The Base Definitions volume of POSIX.1-2017, <<uulliimmiitt..hh>>

CCOOPPYYRRIIGGHHTT
       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 .



IEEE/The Open Group                  2017                            ULIMIT(3)
