Add a safety check to prevent overflow using scope(exit)s
Add a safety check to prevent overflow using scope(exit)s

KBvsMJ/libextobjc,bboyesc/libextobjc,telly/libextobjc,kolyuchiy/libextobjc,jspahrsummers/libextc,jiakai-lian/libextobjc,jspahrsummers/libextc,sunfei/libextobjc,WPDreamMelody/libextobjc,liuruxian/libextobjc,jspahrsummers/libextc,sandyway/libextobjc,sanojnambiar/libextobjc,goodheart/libextobjc