nmake Introduction.ppt

2019/12/6,nmakeIntroduction,2019/12/6,Contents,nmakeoverviewUnderstandingMakefilesUsingVariablesDefiningCustomScanRulesBuildingwithnmakeConclusions,2019/12/6,nmakeoverviewWhatisnmake,Whatisnmake?nmakeisacollectionofenhancementstoUNIXmake(1),usedtosimplifytheprocessofbuildingsoftwaredescendedfromproductdevelopedbyBellLabsResearchalonghistory,overadecadeofdevelopmentanduseusedsuccessfullybyhundredsofprojectswithinLucentandATtheyarethecorecomponentsofthemakefileExample:program:init.cprog.cprogram:init.cprog.cVariablesEditOperatorsTheeditoperatorsprovidedbynmakeformaverypowerfuleditinglanguagethatcanbeusedtoeditthecontentsofavariable.SpecialAtomsSpecialAtomsprovidefinecontroloverassertions,actions,andnmakeprocessing.Therearenearly100ofthem.Example:.FORCECommand-LineOptionsThenmakecommand-lineoptionsprovidecontrolovernmakeexecution.,2019/12/6,UnderstandingMakefilesFormattingaMakefile,Thefirsttargetnameinanyassertionmuststartincolumnone;thetargetsandtheassertionoperatormustbeonthesameline.Thelistofprerequisitescanbeextendedovermultiplelinesbyterminatingalinewithabackslash().Oneormorewhitespacecharactersmusteitherprecedethebackslashorstartthenextline.Succeedinglinesthatstartwithatabareconsideredpartoftheactionblock.Iflinesstartwithoneormorespaces,theyarealsoconsideredpartoftheactionblock,butthatusageisdiscouragedandawarningmessageisgiven,astheresultingmakefilelosessomeportability.,2019/12/6,UnderstandingMakefilesUsingMakefile,Thecommandlinetoexecutenmakeis:nmake-fmakefile_nametargetAnytargetinamakefilecanbereferredtoasanentrypoint.Theusercanspecifythetargetthatistobebuiltonthecommandline.Ifnotargetnamesarespecifiedonthecommandline,nmakewillbuildthefirsttargetintheinputmakefilethatisnotmarkedas.FUNCTIONAL,.OPERATOR,or.REPEAT,andisneitherastatevariablenormetarule.Example:Contentsoffiles.mkFILES=a.cb.ctot.cfilelist:/usr/5bin/ls$(FILES)Runnmake:nmakeffiles.mkfilelist,2019/12/6,UnderstandingMakefilesTheDefaultBaseRulesFile,nmake_install_root/lib/make/Makerules.mk,thedefaultbaserulesfileprovidedwithnmake,isamakefilethatdefinesacollectionofoptions,operators,commonactions,metarules,andvariablessuitableforuseintheUNIXsystemprogrammingenvironment.Itincludespredefinedrulesforavarietyoftransformations.Thusitincludesrulesforcompilingprogramsindifferentlanguages,rulesforcreatingbackupfiles,rulesforcleaningupintermediatefiles,andsoon.,2019/12/6,UnderstandingMakefilesPredefinedSourceDirectory,Sourcedirectoryrulestellnmakewhatdirectoriestolookintofindvarioustypesofsourcefiles.Thefollowingrulesprovideanexampleofsourcedirectoryrules:.SOURCE.C:.src.SOURCE.h:/usr/include.SOURCE.a:/lib/usr/lib,2019/12/6,UnderstandingMakefilesPredefinedAssertionOperators,Allthepredefinedassertionoperators,withtheexceptionofthedependencyassertionoperator(:),aredefinedinthedefaultbaserulesandhavethefollowingsyntax:identifier:Examples:-sourcedependencyoperator:LIBRARY:-createlibraryfromsourcefiles:MAKE:-runnmakeonrhsmakefiles:INSTALLDIR:-installfileindirectory,2019/12/6,UnderstandingMakefilesMetarules,Aseriesofmetarules(alsocalledtransformationrules)isprovidedInthedefaultbaserules.Thesemetarulesdescribehowtobuildafilehavinganameofonepattern(e.g.,prog.o)fromafilehavinganameofadifferentpattern(g.c).Example%.o:%.c(CC)(CCFLAGS)$(CC)$(CCFLAGS)-c$(),2019/12/6,UnderstandingMakefilesCommonActions,Thebaserulesalsodefineagroupofcommonactions,whichareactionsthatarefrequentlyusedbyprojects.Examplesclean-Allgeneratedintermediatefilesareremoved.clobber-Allgeneratedfilesareremoved,excepttheoutputofthecpio,pax,andtarcommonactions.clobber.install-Removesallofthefilesinstalledbytheinstallcommonaction.install-Alltargetfilesoftheassertionswiththepredefinedassertionoperators:,:INSTALL:,:INSTALLDIR:,and:INSTALLMAP:areinstalledinthedirectoryhierarchyrootedat$(INSTALLROOT).,2019/12/6,UnderstandingMakefilesGlobalRules,Project-widerulesintendedtoextendormodifythebaseruledefinitionsmaybeplacedinamakefileknownastheglobalrulesfile.Iftherearenameconflictsinruledefinitionsbetweentheglobalrulesandthebaserules,therulesdefinedintheglobalrulesmakefileoverridethebaserules.ExampleContentsofMakefile:FILES=iomodule.ucprocmod.uctarget:$(FILES)Runnmake:nmakeOutput:make:dontknowhowtomaketargetWriteaglobal.mk:%.c:%.uc$(CP)$()$()oname=$(),2019/12/6,Buildingwithnmake-scalableviewpathingscheme,Whatdoesviewpathingdo?definesavirtualdirectorystructure,whichallowsmultiplenodestobeviewedasasingletreeWhyuseviewpathing?viewpathingprovidesasimplemechanismformaintainingmultipleversionsofaproductusingtheunderlyingfilesystemassistsinavoidingredundantbuildsofpreexistingobjectfilesmaintainedviaVPATHenvironmentvariable(nomakefilechangesrequired)Example:VPATH=/usr/home:/usr/unapproved:/usr/approved,2019/12/6,Buildingwithnmake-scalableviewpathingscheme,VPATH=/usr/home:/usr/unapproved:/usr/approvedSupposetheprogramconsistsofmain.c,alongwithfunctionsandheaderdefinitionsintheremainingfiles.Withviewpathing,abuildforthisexamplewouldusethefollowingversionsofthesefiles:/usr/home/src/f1.c/usr/unapproved/src/f2.c/usr/approved/src/f3.c/usr/unapproved/include/h1.h/usr/approved/include/h2.h/usr/approved/src/cmd/main.c,2019/12/6,Buildingwithnmake-scalableviewpathingscheme,VPATH=/usr/home:/usr/unapproved:/usr/approvedAMakefileforthisexample:,2019/12/6,Buildingwithnmake-Benefitsofviewpathing,Benefitsofviewpathingdevelopersonlyneedtocopychangedsourcefilestoaprivateworkarea,nmakethenlocatestherestusingtheVPATHviewpathingthroughmultiplenodescanrepresentvariousrevisionlevelsofaproduct,thussimplifyingbuildmanagementbuildavoidancebasedonprojectsize,resultantsavingscanbeupwardsof50%ormore,2019/12/6,Buildingwithnmake-incrementalproductbuilds,Whatisanincrementalbuild?abuildwhichonlyusesfilesthatareoutofdatewiththelatestversionWhyuseincrementalbuilds?nmakedeterminesthesetoffilestorebuildbystoring“stateoftheworld”informationinastatefile(.ms)stateinformationrecordstimestampinformationassociatedwithfiles(st_mtime),alongwiththeirdependenciesifafileisoutofdatew.r.t.thetimerecordedinthestatefile,thenitisrebuilt;also,anyitemsthatdependonthefilearerebuiltresult:incrementalbuildsyieldenormoussavingsinbothtimeandresourceallocation,2019/12/6,Buildingwithnmake-incrementalproductbuilds,Example:VPATH=/usr/home:/usr/unapproved:/usr/approved,2019/12/6,Buildingwithnmake-dynamicdependencygeneration,Whatisdynamicdependencygeneration?thecapabilitytodeterminetheimplicitdependenciesbetweenfiles,typicallybetweensourceandheaderfilesbuilt-inrulesareprovidedforscanningmanylanguages(C,C+,Fortran,ESQL/C,nroff/troff,andothers)usercandefinenewscanstrategiesWhyusedynamicdependencygeneration?easesmaintenance-noneedtoassociatefilesexplicitlyinthemakefilesourcefilesandheaderchangesdonotrequirechangemakefilesforC/C+,scannerfollowsthe#includechaintofindoutwhich.hfilesasourcefiledependsuponscanneriscustomizable,evenfordefaultscanrules,2019/12/6,Buildingwithnmake-dynamicdependencygeneration,VPATH=/usr/home:/usr/unapproved:/usr/approvedf1.cincludesh1.hf2.cincludesh2.h,2019/12/6,Conclusions-nmakecorefeatures,scalableviewpathingschemeallowsmultiplebuildenvironmentstocoexistwithminimaleffort