getgrent(3) -- Linux man page

 

NAME

getgrent, setgrent, endgrent - get group file entry  

SYNOPSIS

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

struct group *getgrent(void);

void setgrent(void);

void endgrent(void);
 

DESCRIPTION

The getgrent() function returns a pointer to a structure containing the group information from /etc/group. The first time it is called it returns the first entry; thereafter, it returns successive entries.

The setgrent() function rewinds the file pointer to the beginning of the /etc/group file.

The endgrent() function closes the /etc/group file.

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 */
};

 

RETURN VALUE

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

Upon error, errno may be set. If you want to check its value, set it to zero before the call.  

ERRORS

EINTR
A signal was caught.
EIO
I/O error.
EMFILE
The calling process already has too many open files.
ENFILE
Too many open files in the system.
ENOMEM Insufficient memory to allocate group information structure.
 

FILES

/etc/group

 group database file
 

CONFORMING TO

SVID 3, BSD 4.3, POSIX 1003.1-2003.  

SEE ALSO

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