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These functions operate on the group database file which
is described in Each line of the database is defined by the structure
found in the include file struct group { char *gr_name; /* group name
*/
char *gr_passwd; /* group password */
gid_t gr_gid; /* group id */
char **gr_mem; /* group members */
}; The functions and search the group database for the given group
name pointed to by or the group id pointed to by respectively, returning
the first one encountered. Identical group names or group gids may result
in undefined behavior. The function sequentially reads the group database
and is intended for programs that wish to step through the complete list
of groups. All three routines will open the group file for reading, if
necessary. The function opens the file, or rewinds it if it is already
open. If is non-zero, file descriptors are left open, significantly speeding
functions subsequent calls. This functionality is unnecessary for as it
doesn’t close its file descriptors by default. It should also be noted that
it is dangerous for long-running programs to use this functionality as the
group file may be updated. The function is equivalent to with an argument
of zero. The function closes any open files.
The functions
and return a pointer to the group entry if successful; if end-of-file
is reached or an error occurs a null pointer is returned. The function
returns the value 1 if successful, otherwise the value 0 is returned. The
and functions have no return value.
group database file
The functions and appeared in The functions and appeared
in
The historic function which allowed the specification
of alternate password databases, has been deprecated and is no longer available.
The functions and leave their results in an internal static object
and return a pointer to that object. Subsequent calls to the same function
will modify the same object. The functions and are fairly useless in
a networked environment and should be avoided, if possible.
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