SEEKDIR(3)                 POSIX Programmer's Manual                SEEKDIR(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
       seekdir -- set the position of a directory stream

SSYYNNOOPPSSIISS
       #include <dirent.h>

       void seekdir(DIR *_d_i_r_p, long _l_o_c);

DDEESSCCRRIIPPTTIIOONN
       The _s_e_e_k_d_i_r() function shall set the position of the next _r_e_a_d_d_i_r()
       operation on the directory stream specified by _d_i_r_p to the position
       specified by _l_o_c.  The value of _l_o_c should have been returned from an
       earlier call to _t_e_l_l_d_i_r() using the same directory stream. The new
       position reverts to the one associated with the directory stream when
       _t_e_l_l_d_i_r() was performed.

       If the value of _l_o_c was not obtained from an earlier call to _t_e_l_l_d_i_r(),
       or if a call to _r_e_w_i_n_d_d_i_r() occurred between the call to _t_e_l_l_d_i_r() and
       the call to _s_e_e_k_d_i_r(), the results of subsequent calls to _r_e_a_d_d_i_r() are
       unspecified.

RREETTUURRNN VVAALLUUEE
       The _s_e_e_k_d_i_r() function shall not return a value.

EERRRROORRSS
       No errors are defined.

       _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
       None.

RRAATTIIOONNAALLEE
       The original standard developers perceived that there were restrictions
       on the use of the _s_e_e_k_d_i_r() and _t_e_l_l_d_i_r() functions related to
       implementation details, and for that reason these functions need not be
       supported on all POSIX-conforming systems. They are required on
       implementations supporting the XSI option.

       One of the perceived problems of implementation is that returning to a
       given point in a directory is quite difficult to describe formally, in
       spite of its intuitive appeal, when systems that use B-trees, hashing
       functions, or other similar mechanisms to order their directories are
       considered. The definition of _s_e_e_k_d_i_r() and _t_e_l_l_d_i_r() does not specify
       whether, when using these interfaces, a given directory entry will be
       seen at all, or more than once.

       On systems not supporting these functions, their capability can
       sometimes be accomplished by saving a filename found by _r_e_a_d_d_i_r() and
       later using _r_e_w_i_n_d_d_i_r() and a loop on _r_e_a_d_d_i_r() to relocate the
       position from which the filename was saved.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       _f_d_o_p_e_n_d_i_r(), _r_e_a_d_d_i_r(), _t_e_l_l_d_i_r()

       The Base Definitions volume of POSIX.1-2017, <<ddiirreenntt..hh>>, <<ssyyss__ttyyppeess..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                           SEEKDIR(3)
