1GETGRENT(3)                Linux Programmer's Manual               GETGRENT(3)
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NAME

6       getgrent, setgrent, endgrent - get group file entry
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SYNOPSIS

9       #include <sys/types.h>
10       #include <grp.h>
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12       struct group *getgrent(void);
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14       void setgrent(void);
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16       void endgrent(void);
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18   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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20       getgrent(), setgrent(), endgrent(): _SVID_SOURCE || _BSD_SOURCE ||
21       _XOPEN_SOURCE >= 500
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DESCRIPTION

24       The getgrent() function returns a pointer to a structure containing the
25       broken-out  fields  of  a record in the group database (e.g., the local
26       group file /etc/group, NIS, and LDAP).  The first time it is called  it
27       returns the first entry; thereafter, it returns successive entries.
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29       The setgrent() function rewinds to the beginning of the group database,
30       to allow repeated scans.
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32       The endgrent() function is used to close the group database  after  all
33       processing has been performed.
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35       The group structure is defined in <grp.h> as follows:
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37           struct group {
38               char   *gr_name;       /* group name */
39               char   *gr_passwd;     /* group password */
40               gid_t   gr_gid;        /* group ID */
41               char  **gr_mem;        /* group members */
42           };
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RETURN VALUE

45       The getgrent() function returns a pointer to a group structure, or NULL
46       if there are no more entries or an error occurs.
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48       Upon error, errno may be set.  If one wants to check  errno  after  the
49       call, it should be set to zero before the call.
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51       The  return value may point to a static area, and may be overwritten by
52       subsequent calls to getgrent(), getgrgid(3), or getgrnam(3).   (Do  not
53       pass the returned pointer to free(3).)
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ERRORS

56       EINTR  A signal was caught.
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58       EIO    I/O error.
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60       EMFILE The calling process already has too many open files.
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62       ENFILE Too many open files in the system.
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64       ENOMEM Insufficient memory to allocate group structure.
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66       ERANGE Insufficient buffer space supplied.
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FILES

69       /etc/group
70              local group database file
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CONFORMING TO

73       SVr4, 4.3BSD, POSIX.1-2001.
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SEE ALSO

76       fgetgrent(3), getgrent_r(3), getgrgid(3), getgrnam(3), getgrouplist(3),
77       putgrent(3)
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COLOPHON

80       This page is part of release 3.22 of the Linux  man-pages  project.   A
81       description  of  the project, and information about reporting bugs, can
82       be found at http://www.kernel.org/doc/man-pages/.
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86                                  2009-03-30                       GETGRENT(3)
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