getgrent, setgrent, endgrent — get group file entry
#include <sys/types.h> #include <grp.h>
struct group
*getgrent( |
void) ; |
void
setgrent( |
void) ; |
void
endgrent( |
void) ; |
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Note | ||||||
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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 getgrent
() 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 */};
For more information about the fields of this structure, see group(5).
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.
The return value may point to a static area, and may be
overwritten by subsequent calls to getgrent
(), getgrgid(3), or getgrnam(3). (Do not pass
the returned pointer to free(3).)
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 structure.
Insufficient buffer space supplied.
fgetgrent(3), getgrent_r(3), getgrgid(3), getgrnam(3), getgrouplist(3), putgrent(3), group(5)