labview变量类型及处理

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1、DataManipulationOverviewandApplicationsAgendaOverviewofLabVIEWdatatypesManipulatingLabVIEWdatatypesChangingdatatypesBytelevelmanipulationofdataBitlevelmanipulationofdataApplicationsinvolvingdatamanipulationDataencryptionInstrumentI/OByteUnsignedByteWord

2、UnsignedWordLongUnsignedLongSinglePrecisionDoublePrecisionExtendedPrecision8bits8bits16bits16bits32bits32bits8bytesSun:16bytesWindows/Linux:10bytesPowerMac:Double/Double4bytesLabVIEWDataTypes:NumericLabVIEWDataTypes:ArraysStoredashandlescontaining:Sizeo

3、feachdimension(inunsignedlongintegers,U32s)Data(sizeofelementsvariesbutisconsistentthrougharray)Toaligndatacorrectly,afewbytesofpaddingmaybeaddedbeforethefirstelementofdataArrayisacontinuousblockofmemory1DarrayofSGLs4DarrayofI16sLabVIEWDataTypes:OthersB

4、ooleans:8bitsAllzeros=FALSE,nonzero=TRUEStrings:1DarrayofunsignedbytesArrayofStrings:arrayofU32handlestostringlocationsPaths:handlescontainingpathtypeandnumberofpathcomponentsinU16sByte0,1:0(abs),1(rel),3(UNC)Byte2,3#ofpathcomponentsLabVIEWDataTypes:Clu

5、stersDatastoredaccordingtoclusterorderScalardatastoreddirectlyinclusterArrays,strings,andpathsstoredasahandletothememorylocationwherethedataisstoredPaddingmayneedtobeadded,dependingonOSExample:clusterofSGL,EXT,and1DarrayofU16sWindowsMacSunFlattenedDataF

6、latdatatakesupacontinuousblockofmemoryScalarandarraynumericsareflatStringsareflatArraysofstringsarenotflatClustersmaybeflat(ifsimplenumerics,forexample)DuringFileI/OLabVIEWautomaticallyflattensalldatatoeasestoragetodiskFlatten/Unflattento/fromStringfunc

7、tionsperformthesameoperationsinmemoryFlattenedDataFlatteneddatanormalizedtostandardformforplatformindependenceNumericdatainbigendianform(MSBfirst)Windowsappsmayneedtobelittleendian–swapbytesSunformatforextendedprecisionnumbersFlattenedformdoesnothavedat

8、aencodingWhenunflattening,datatypeneedstobeknownTypedescriptorusedtodefinedatatype*demoTypeDescriptorsSequenceofwordintegersthatcandescribeanydatatypeinLabVIEW.I16sizeinbytes(includinglengthword)