OS ▁and ▁iOS ▁are ▁derived . ▁Port able ▁Object ive - C ▁programs ▁that ▁do ▁not ▁use ▁Apple ▁libraries , ▁or ▁those ▁using ▁parts ▁that ▁may ▁be ▁port ed ▁or ▁re im plement ed ▁for ▁other ▁systems , ▁can ▁also ▁be ▁compiled ▁for ▁any ▁system ▁supported ▁by ▁GNU ▁Comp iler ▁Collection ▁( G CC ) ▁or ▁Cl ang . ▁ ▁Object ive - C ▁source ▁code ▁' implementation ' ▁program ▁files ▁usually ▁have ▁ ▁filename ▁extensions , ▁while ▁Object ive - C ▁' header / interface ' ▁files ▁have ▁ ▁extensions , ▁the ▁same ▁as ▁C ▁header ▁files . ▁Object ive - C ++ ▁files ▁are ▁denoted ▁with ▁a ▁ ▁file ▁extension . ▁ ▁History ▁Object ive - C ▁was ▁created ▁primarily ▁by ▁Brad ▁C ox ▁and ▁Tom ▁Love ▁in ▁the ▁early ▁ 1 9 8 0 s ▁at ▁their ▁company ▁Product ivity ▁Product s ▁International . ▁ ▁Le ading ▁up ▁to ▁the ▁creation ▁of ▁their ▁company , ▁both ▁had ▁been ▁introduced ▁to ▁Small t alk ▁while ▁at ▁IT T ▁Corporation ' s ▁Program ming ▁Technology ▁Center ▁in ▁ 1 9 8 1 . ▁The ▁earliest ▁work ▁on ▁Object ive - C ▁traces ▁back ▁to ▁around ▁that ▁time . ▁C ox ▁was ▁intr igu ed ▁by ▁problems ▁of ▁true ▁re us ability ▁in ▁software ▁design ▁and ▁programming . ▁He ▁realized ▁that ▁a ▁language ▁like ▁Small t alk ▁would ▁be ▁in valu able ▁in ▁building ▁development ▁environments ▁for ▁system ▁developers ▁at ▁IT T . ▁However , ▁he ▁and ▁Tom ▁Love ▁also ▁recognized ▁that ▁back