var result *_C_struct_group
	errno = unix.Getgrnam(name, &grp, buf, size, &result)
	return grp, result != nil, errno
}

func _C_getgrgid_r(gid _C_gid_t, buf *_C_char, size _C_size_t) (grp _C_struct_group, found bool, errno syscall.Errno) {
	var result *_C_struct_group
	errno = unix.Getgrgid(gid, &grp, buf, size, &result)
	return grp, result != nil, errno
}

	var f, e _C_int
	grp = C.mygetgrnam_r(name, buf, size, &f, &e)
	return grp, f != 0, syscall.Errno(e)
}

func _C_getgrgid_r(gid _C_gid_t, buf *_C_char, size _C_size_t) (grp _C_struct_group, found bool, errno syscall.Errno) {
	var f, e _C_int
	grp = C.mygetgrgid_r(_C_int(gid), buf, size, &f, &e)
	return grp, f != 0, syscall.Errno(e)
}

func lookupUnixGid(gid int) (*Group, error) {
	var grp _C_struct_group
	var found bool

	err := retryWithBuffer(groupBuffer, func(buf []byte) syscall.Errno {
		var errno syscall.Errno
		grp, found, errno = _C_getgrgid_r(_C_gid_t(gid),
			(*_C_char)(unsafe.Pointer(&buf[0])), _C_size_t(len(buf)))
		return syscall.Errno(errno)
	})
	if err == syscall.ENOENT || (err == nil && !found) {
		return nil, UnknownGroupIdError(strconv.Itoa(gid))