.Dd February 3, 2005
.Dt MBR_CHECKMEMBERSHIP 3
.Os
.Sh NAME
.Nm mbr_check_membership
.Nd check whether a user is a member of a group
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In membership.h
.Ft int
.Fn mbr_check_membership "uuid_t user" "uuid_t group" "int* ismember"
.Sh DESCRIPTION
.Fn mbr_uid_to_uuid
eliminates the 16 group limit inherent in getgroups(3).  It will always return if
a given user is a member of a given group, even if the membership is due to nesting of groups.
.Fa ismember
is set to 1 if the user is a member of the group, and 0 otherwise.  
.Pp
There are two special cases. If the two uuids are equal, then 
.Fa ismember
is set to 1.  If the
.Fa group
uuid is equal to the reserved "everyone" uuid (ABCDEFAB-CDEF-ABCD-EFAB-CDEF0000000C), then
.Fa ismember
will be set to 1 for any valid user.
.Sh RETURN VALUES
.Fn mbr_uid_to_uuid
will return EIO if it is unable to talk to memberd.  If
.Fa user
cannot be found it will return ENOENT.  Note that it makes no attempt to determine whether
.Fa group
exists or not.  Querying membership about a nonexistant group will simply return the user is not a
member.
.Sh SEE ALSO
.Xr mbr_uid_to_uuid 3