getgrent_r(3)              Library Functions Manual              getgrent_r(3)

<?><?><?><?><?><?><?><?><?><?><?><?>
       getgrent_r, fgetgrent_r - <?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?> <?><?> <?><?><?><?><?> <?><?><?><?><?>
       (<?><?><?><?><?><?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?>)

<?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?> C (libc, -lc)

<?><?><?><?><?>
       #include <grp.h>

       int getgrent_r(size_t size;
                      struct group *restrict gbuf,
                      char buf[restrict size], size_t size,
                      struct group **restrict gbufp);
       int fgetgrent_r(size_t size;
                      FILE *restrict stream, struct group *restrict gbuf,
                      char buf[restrict size], size_t size,
                      struct group **restrict gbufp);

   <?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?>
   <?><?><?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?> <?><?><?> glibc
   (<?><?>. feature_test_macros(7)):

       getgrent_r():
           _GNU_SOURCE

       fgetgrent_r():
           <?><?><?><?><?><?><?> <?> glibc 2.19:
               _DEFAULT_SOURCE
           glibc 2.19 <?> <?><?><?><?><?><?>:
               _SVID_SOURCE

<?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?> getgrent_r() <?> fgetgrent_r()
       <?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?> getgrent(3) <?> fgetgrent(3).
       <?><?><?><?><?><?> <?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?> <?><?><?><?><?><?> <?><?> <?><?><?><?><?><?>,
       <?><?><?><?><?><?><?><?><?><?><?><?><?><?><?><?><?><?><?> setgrent(3).
       <?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?> <?><?><?><?><?><?>
       <?><?> stream.

       <?><?><?><?><?><?><?><?><?> group <?><?><?><?><?><?><?><?><?><?> <?>
       <grp.h> <?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?>:

           struct group {
               char   *gr_name;        /* <?><?><?> <?><?><?><?><?><?> */
               char   *gr_passwd;      /* <?><?><?><?><?><?> <?><?><?><?><?><?> */
               gid_t   gr_gid;         /* ID <?><?><?><?><?><?> */
               char  **gr_mem;         /* <?><?><?><?><?><?>, <?><?><?><?><?><?><?><?><?><?>
                                          <?><?><?><?> <?><?><?><?><?><?> <?><?><?><?><?><?>, <?><?><?><?><?><?><?><?><?><?><?><?><?><?> NULL */
           };

       <?><?><?><?><?><?><?><?><?> <?> <?><?><?><?><?> <?><?><?><?>
       <?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?> <?> group(5).

       The nonreentrant functions return a pointer to static storage, where
       this static storage contains further pointers to group name, password,
       and members.  The reentrant functions described here return all of that
       in caller-provided buffers.  First of all there is the buffer gbuf that
       can hold a struct group.  And next the buffer buf of size size that can
       hold additional strings.  The result of these functions, the
       struct group read from the stream, is stored in the provided buffer
       *gbuf, and a pointer to this struct group is returned in *gbufp.

<?><?><?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?>
       On success, these functions return 0 and *gbufp is a pointer to the
       struct group.  On error, these functions return an error value and
       *gbufp is NULL.

<?><?><?><?><?><?>
       ENOENT <?><?><?><?><?><?> <?><?><?><?><?><?><?> <?><?><?>.

       ERANGE <?><?><?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?> <?>
              <?><?><?><?><?><?>. <?><?><?><?><?><?><?><?><?><?> <?><?><?>
              <?><?><?> <?> <?><?><?><?><?><?><?> <?><?><?><?><?><?><?>.

<?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?> <?> attributes(7).

       +----------------------------+----------------------------------------------------------+--------------------------+
       |<?><?><?><?><?><?><?><?><?> | <?><?><?><?><?><?><?>                                    | <?><?><?><?><?><?><?><?> |
       +----------------------------+----------------------------------------------------------+--------------------------+
       |getgrent_r()                | <?><?><?><?><?><?><?><?><?><?><?><?> <?> <?><?><?><?><?> | MT-Unsafe race:grent     |
       |                            |                                                          | locale                   |
       +----------------------------+----------------------------------------------------------+--------------------------+
       |fgetgrent_r()               | <?><?><?><?><?><?><?><?><?><?><?><?> <?> <?><?><?><?><?> | MT-Safe                  |
       +----------------------------+----------------------------------------------------------+--------------------------+
       In the above table, grent in race:grent signifies that if any of the
       functions setgrent(3), getgrent(3), endgrent(3), or getgrent_r() are
       used in parallel in different threads of a program, then data races
       could occur.

<?><?><?><?><?><?>
       Other systems use the prototype

           struct group *getgrent_r(struct group *grp, char buf[.size],
                                    int size);

       <?><?><?>, <?><?><?><?><?>,

           int getgrent_r(struct group *grp, char buf[.size], int size,
                          FILE **gr_fp);

<?><?><?><?><?><?><?><?><?>
       GNU.

<?><?><?><?><?><?><?>
       <?><?><?> <?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?> <?>
       <?><?><?><?><?>, <?><?><?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?> POSIX <?><?><?><?><?><?><?> <?><?><?><?>
       getpwnam_r(3).

<?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?> getgrent_r() <?><?> <?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?><?><?><?>, <?><?><?> <?><?><?>
       <?><?><?> <?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?>
       <?><?><?><?><?><?><?> <?><?><?><?><?><?> <?> <?><?><?><?><?><?> <?>
       <?><?><?><?><?><?><?> <?><?><?><?><?><?>.

<?><?><?><?><?><?><?>
       #define _GNU_SOURCE
       #include <grp.h>
       #include <stdint.h>
       #include <stdio.h>
       #include <stdlib.h>
       #define BUFLEN 4096

       int
       main(void)
       {
           struct group grp;
           struct group *grpp;
           char buf[BUFLEN];
           int i;

           setgrent();
           while (1) {
               i = getgrent_r(&grp, buf, sizeof(buf), &grpp);
               if (i)
                   break;
               printf("%s (%jd):", grpp->gr_name, (intmax_t) grpp->gr_gid);
               for (size_t j = 0; ; j++) {
                   if (grpp->gr_mem[j] == NULL)
                       break;
                   printf(" %s", grpp->gr_mem[j]);
               }
               printf("\n");
           }
           endgrent();
           exit(EXIT_SUCCESS);
       }

<?><?><?><?><?><?><?><?> <?><?><?><?><?>
       fgetgrent(3), getgrent(3), getgrgid(3), getgrnam(3), putgrent(3),
       group(5)

<?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?> <?><?><?><?><?><?><?> <?><?><?><?>
       <?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?>(<?>) Azamat Hackimov
       <azamat.hackimov@gmail.com>, Dmitry Bolkhovskikh <d20052005@yandex.ru>,
       Vladislav <ivladislavefimov@gmail.com>, Yuri Kozlov
       <yuray@komyakino.ru> <?> <?><?><?><?> <?><?><?><?><?><?>
       <pavia00@gmail.com>

       <?><?><?><?> <?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?><?><?>; <?><?>
       <?><?><?><?><?><?><?><?><?><?><?><?><?><?><?><?> <?><?>
       <?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?> GNU (GNU General Public License - GPL,
       <https://www.gnu.org/licenses/gpl-3.0.html> <?><?><?><?><?><?> 3
       <?><?><?> <?><?><?><?><?> <?><?><?><?><?><?><?>) <?>
       <?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?>, <?><?> <?><?><?> <?><?><?><?><?>-<?><?><?><?>
       <?><?><?><?><?><?><?><?>.

       <?><?><?><?> <?><?> <?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?>-<?><?><?><?> <?><?><?><?><?><?> <?>
       <?><?><?><?><?><?><?><?> <?><?><?><?> <?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?>, <?><?><?><?><?><?><?><?><?><?>,
       <?><?><?><?><?><?><?><?> <?><?> <?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?><?>(<?><?>) <?><?> <?><?><?>(<?><?>)
       <?><?><?><?><?><?>(<?><?>) <?><?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?> <?><?><?> <?><?> <?><?><?><?><?><?> <?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?><?>
       <<debian-l10n-russian@lists.debian.org>>.

<?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?> Linux 6.17
                       8 <?><?><?><?><?><?><?> 2026 <?>.         getgrent_r(3)