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

getgrent, setgrent, endgrent - get group file entry

#include <sys/types.h>
#include <grp.h>

struct group *getgrent(void);

void setgrent(void);

void endgrent(void);

The getgrent() function returns a pointer to a structure containing the broken-out fields of a record in the group database (e.g., the local group file /etc/group, NIS, and LDAP). The first time it is called it returns the first entry; thereafter, it returns successive entries.

The setgrent() function rewinds to the beginning of the group database, to allow repeated scans.

The endgrent() function is used to close the group database after all processing has been performed.

The group structure is defined in <grp.h> as follows:

struct group {

    char   *gr_name;       /* group name */

    char   *gr_passwd;     /* group password */

    gid_t   gr_gid;        /* group ID */

    char  **gr_mem;        /* group members */
};

The getgrent() function returns a pointer to a group structure, or NULL if there are no more entries or an error occurs.

Upon error, errno may be set. If one wants to check errno after the call, it should be set to zero before the call.

A signal was caught.
I/O error.
The calling process already has too many open files.
Too many open files in the system.
Insufficient memory to allocate group information structure.
Insufficient buffer space supplied.

/etc/group
local group database file

SVID 3, 4.3BSD, POSIX 1003.1-2003.

fgetgrent(3), getgrent_r(3), getgrgid(3), getgrnam(3), putgrent(3)

1993-04-04

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