This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface

       None.

       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                                         grp.h(7POSIX)

       The <grp.h> header shall declare the group structure, which shall include the following members:

           char   *gr_name The name of the group.
           gid_t   gr_gid  Numerical group ID.
           char  **gr_mem  Pointer to a null-terminated array of character
                           pointers to member names.

       The <grp.h> header shall define the gid_t and size_t types as described in <sys/types.h>.

       The following shall be declared as functions and may also be defined as macros. Function prototypes shall
       be provided.

           void           endgrent(void);
           struct group  *getgrent(void);
           struct group  *getgrgid(gid_t);
           int            getgrgid_r(gid_t, struct group *, char *,
                              size_t, struct group **);
           struct group  *getgrnam(const char *);
           int            getgrnam_r(const char *, struct group *, char *,
                              size_t , struct group **);
           void           setgrent(void);

       Thefollowingsectionsareinformative.

       None.

       grp.h — group structure

       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.

       None.

<sys_types.h>

       The System Interfaces volume of POSIX.1‐2017, endgrent(), getgrgid(), getgrnam()

       #include <grp.h>