sticky?()
public
Returns true if stat has its sticky bit set, false if it doesn’t
or if the operating system doesn’t support this feature.
File.stat("testfile").sticky?
static VALUE
rb_stat_sticky(VALUE obj)
{
#ifdef S_ISVTX
if (get_stat(obj)->st_mode & S_ISVTX) return Qtrue;
#endif
return Qfalse;
}