ENDGRENT(3)                POSIX Programmer's Manual               ENDGRENT(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
       endgrent, getgrent, setgrent -- group database entry functions

SSYYNNOOPPSSIISS
       #include <grp.h>

       void endgrent(void);
       struct group *getgrent(void);
       void setgrent(void);

DDEESSCCRRIIPPTTIIOONN
       The _g_e_t_g_r_e_n_t() function shall return a pointer to a structure
       containing the broken-out fields of an entry in the group database. If
       the group database is not already open, _g_e_t_g_r_e_n_t() shall open it and
       return a pointer to a ggrroouupp structure containing the first entry in the
       database. Thereafter, it shall return a pointer to a ggrroouupp structure
       containing the next ggrroouupp structure in the group database, so
       successive calls may be used to search the entire database.

       An implementation that provides extended security controls may impose
       further implementation-defined restrictions on accessing the group
       database. In particular, the system may deny the existence of some or
       all of the group database entries associated with groups other than
       those groups associated with the caller and may omit users other than
       the caller from the list of members of groups in database entries that
       are returned.

       The _s_e_t_g_r_e_n_t() function shall rewind the group database so that the
       next _g_e_t_g_r_e_n_t() call returns the first entry, allowing repeated
       searches.

       The _e_n_d_g_r_e_n_t() function shall close the group database.

       The _s_e_t_g_r_e_n_t() and _e_n_d_g_r_e_n_t() functions shall not change the setting of
       _e_r_r_n_o if successful.

       On error, the _s_e_t_g_r_e_n_t() and _e_n_d_g_r_e_n_t() functions shall set _e_r_r_n_o to
       indicate the error.

       Since no value is returned by the _s_e_t_g_r_e_n_t() and _e_n_d_g_r_e_n_t() functions,
       an application wishing to check for error situations should set _e_r_r_n_o
       to 0, then call the function, then check _e_r_r_n_o.

       These functions need not be thread-safe.

RREETTUURRNN VVAALLUUEE
       On successful completion, _g_e_t_g_r_e_n_t() shall return a pointer to a ggrroouupp
       structure. On end-of-file, _g_e_t_g_r_e_n_t() shall return a null pointer and
       shall not change the setting of _e_r_r_n_o.  On error, _g_e_t_g_r_e_n_t() shall
       return a null pointer and _e_r_r_n_o shall be set to indicate the error.

       The application shall not modify the structure to which the return
       value points, nor any storage areas pointed to by pointers within the
       structure. The returned pointer, and pointers within the structure,
       might be invalidated or the structure or the storage areas might be
       overwritten by a subsequent call to _g_e_t_g_r_g_i_d(), _g_e_t_g_r_n_a_m(), or
       _g_e_t_g_r_e_n_t().  The returned pointer, and pointers within the structure,
       might also be invalidated if the calling thread is terminated.

EERRRROORRSS
       These functions may fail if:

       EEIINNTTRR  A signal was caught during the operation.

       EEIIOO    An I/O error has occurred.

       In addition, the _g_e_t_g_r_e_n_t() and _s_e_t_g_r_e_n_t() functions may fail if:

       EEMMFFIILLEE All file descriptors available to the process are currently
              open.

       EENNFFIILLEE The maximum allowable number of files is currently open in the
              system.

       _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
       These functions are provided due to their historical usage.
       Applications should avoid dependencies on fields in the group database,
       whether the database is a single file, or where in the file system name
       space the database resides. Applications should use _g_e_t_g_r_n_a_m() and
       _g_e_t_g_r_g_i_d() whenever possible because it avoids these dependencies.

RRAATTIIOONNAALLEE
       None.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       _e_n_d_p_w_e_n_t(), _g_e_t_g_r_g_i_d(), _g_e_t_g_r_n_a_m(), _g_e_t_l_o_g_i_n()

       The Base Definitions volume of POSIX.1-2017, <<ggrrpp..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                          ENDGRENT(3)
