setgrent(3)

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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DESCRIPTION

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

40       The getgrent() function returns a pointer to a group structure, or NULL
41       if there are no more entries or an error occurs.
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43       Upon  error,  errno  may be set.  If one wants to check errno after the
44       call, it should be set to zero before the call.
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ERRORS

47       EINTR  A signal was caught.
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49       EIO    I/O error.
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51       EMFILE The calling process already has too many open files.
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53       ENFILE Too many open files in the system.
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55       ENOMEM Insufficient memory to allocate group information structure.
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57       ERANGE Insufficient buffer space supplied.
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FILES

60       /etc/group
61              local group database file
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CONFORMING TO

64       SVr4, 4.3BSD, POSIX.1-2001.
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