X# Runtime and VO SDK Reference
X# Runtime and VO SDK Reference
XSharp.RT Namespace
Functions, Globals and Defines
List of Functions
_accept Function
_ArrayToObjectArray Function
_ArrayToUsualArray Function
_Break Function
_CallClipFunc Function
_GetMRandID Function
_MClear Function
_MRelease Function
_MRestore Function
_MSave Function
_MxRelease Function
_NoAlias Function
_ObjectArrayToUsualArray Function
_PrivateCount Function
_PrivateEnum Function
_PrivateFirst Function
_PrivateNext Function
_PublicCount Function
_PublicEnum Function
_PublicFirst Function
_PublicNext Function
_RegisterExit Function
_Select Function
_SelectString Function
_Str Function
_Str3 Function
_UsualArrayToObjectArray Function
_VoDbErrInfoPtr Function
_wait Function
AAdd Function
Abs Function
AbsFloat Function
AClone Function
ACloneShallow Function
ACopy Function
ACos Function
ACot Function
ADel Function
ADim Function
ADimPic Function
ADir Function
AEval Function
AEvalA Function
AEvalOld Function
AFields Function
AFill Function
AIns Function
ALen Function
Alias Function
Alias0 Function
Alias0Sym Function
AllowCollectThread Function
Ansi2OemBuff Function
AReplicate Function
Array Function
ArrayBuild Function
ArrayCreate Function
ArrayDeProtect Function
ArrayGet Function
ArrayInit Function
ArrayNew Function
ArrayProtect Function
ArrayPut Function
ArrayStore Function
ArraySwap Function
AScan Function
AScanBin Function
AScanBinExact Function
AScanExact Function
ASend Function
AsHexString Function
ASin Function
ASize Function
ASort Function
AsPadr Function
AsString Function
AsSymbol Function
ATail Function
ATan Function
Atan2 Function
ATrueDel Function
Between Function
Bin2Date Function
Bin2F Function
Bin2Logic Function
BLOBDirectExport Function
BLOBDirectGet Function
BLOBDirectImport Function
BLOBDirectPut Function
BLOBExport Function
BLOBGet Function
BLOBImport Function
BLOBRootGet Function
BLOBRootLock Function
BLOBRootPut Function
BLOBRootUnlock Function
Bof Function
CanBreak Function
CDoW Function
Ceil Function
CheckInstanceOf Function
ClassCount Function
ClassList Function
ClassName Function
ClassTree Function
ClassTreeClass Function
cls Function
CMonth Function
Col Function
Collect Function
CollectCount Function
CollectForced Function
ConcatAtom Function
ConcatAtom3 Function
ConcatAtom4 Function
ConcatAtom5 Function
ConDate Function
Cos Function
Cot Function
CParamCount Function
CreateInstance Function
CSend Function
CToD Function
CToDAnsi Function
Date Function
Date2Bin Function
Day Function
DbApp Function
DbAppDelim Function
DbAppend Function
DbAppSdf Function
DbBlobInfo Function
DbBuffRefresh Function
DbClearFilter Function
DbClearIndex Function
DBClearOrderCondition Function
DbClearRelation Function
DbClearScope Function
DbCloseAll Function
DbCloseArea Function
DbCommit Function
DbCommitAll Function
DbContinue Function
DbCopy Function
DbCopyDelim Function
DbCopySDF Function
DbCopyStruct Function
DbCopyXStruct Function
DbCreate Function
DbCreateIndex Function
DbCreateOrder Function
DbDelete Function
DbDeleteOrder Function
DbDriver Function
DbEval Function
DBF Function
DbFieldInfo Function
DBFileCopy Function
DbFilter Function
DbGetSelect Function
DbGoBottom Function
DbGoto Function
DbGoTop Function
DbInfo Function
DbJoin Function
DbJoinAppend Function
DbLocate Function
DbMemoExt Function
DbMemoField Function
DbMoveToDisk Function
DbMoveToMemory Function
DbOrderInfo Function
DbPack Function
DbRecall Function
DbRecordInfo Function
DbReindex Function
DbRelation Function
DbRLock Function
DbRLockList Function
DbRSelect Function
DbRUnLock Function
DbScope Function
DbSeek Function
DbSelect Function
DbSelectArea Function
DbSetDriver Function
DbSetFilter Function
DbSetFound Function
DbSetIndex Function
DbSetOrder Function
DbSetOrderCondition Function
DbSetRelation Function
DbSetScope Function
DbSetSelect Function
DbSkip Function
DbSort Function
DbStruct Function
DbSymSelect Function
DbTotal Function
DbTrans Function
DbUnLock Function
DbUnLockAll Function
DbUpdate Function
DbUseArea Function
DbZap Function
DebOut Function
Default Function
Deleted Function
Descend Function
DescendA Function
DirChange Function
Directory Function
DirMake Function
DirRemove Function
DiskChange Function
DoError Function
DoW Function
DToC Function
DToR Function
DToS Function
Empty Function
EmptyField Function
EmptyPSZ Function
EmptyRecord Function
EmptyString Function
EmptyUsual Function
EnableLBOptimizations Function
EnforceNumeric Function
EnforceType Function
Eof Function
ErrorBlock Function
Eval Function
Evaluate Function
Exp Function
F2Bin Function
Fact Function
FCount Function
FieldBlock Function
FieldBlockSym Function
FieldGet Function
FieldGetAlias Function
FieldGetArea Function
FieldGetBytes Function
FieldGetSelect Function
FieldGetSym Function
FieldName Function
FieldPos Function
FieldPosSym Function
FieldPut Function
FieldPutAlias Function
FieldPutArea Function
FieldPutBytes Function
FieldPutSelect Function
FieldPutSym Function
FieldSym Function
FieldWBlock Function
FieldWBlockSym Function
FindClass Function
Float2Long Function
FloatFormat Function
Flock Function
Floor Function
Found Function
FParamCount Function
Frac Function
FRead Function
FRead3 Function
FRead4 Function
FReadLine Function
FReadText3 Function
FSeek Function
FWrite Function
FWrite3 Function
FWriteLine Function
FWriteText Function
GetRTFullPath Function
GetThreadCount Function
GetTickCountLow Function
Header Function
InCollect Function
IndexCount Function
IndexExt Function
IndexHPLock Function
IndexKey Function
IndexOrd Function
InList Function
InListExact Function
Integer Function
IsAccess Function
IsArray Function
IsAssign Function
IsByRef Function
IsClass Function
IsClassOf Function
IsCodeBlock Function
IsCurrency Function
IsDate Function
IsDateTime Function
IsDecimal Function
IsFloat Function
IsFractional Function
IsInstanceOf Function
IsInstanceOfUsual Function
IsInt64 Function
IsInteger Function
IsLogic Function
IsLong Function
IsMethod Function
IsMethodClass Function
IsMethodUsual Function
IsNil Function
IsNumeric Function
IsObject Function
IsPtr Function
IsString Function
IsSymbol Function
IVarGet Function
IVarGetInfo Function
IVarGetSelf Function
IvarList Function
IvarListClass Function
IVarPut Function
IVarPutInfo Function
IVarPutSelf Function
JCDOW Function
JCMONTH Function
JCYEAR Function
LastRec Function
Len Function
LOG Function
Log10 Function
LUpdate Function
MAssign Function
Max Function
MaxAtom Function
MCompile Function
Mem2String Function
MemAlloc Function
MemAtSpecial Function
MemByte Function
MemCAlloc Function
MemChr Function
MemClear Function
MemComp Function
MemCopy Function
MemCopyString Function
MemDWord Function
MemFree Function
MemGrpAlloc Function
MemGrpCAlloc Function
MemGrpClose Function
MemGrpEnum Function
MemGrpOpen Function
MemInt Function
MemLen Function
MemLong Function
MemLower Function
MemMove Function
MemoTran Function
MemRealloc Function
MemSet Function
MemShort Function
MemTotal Function
MemTrace Function
MemUpper Function
MemVarBlock Function
MemVarBlockSym Function
MemVarClear Function
MemVarGet Function
MemVarGetSym Function
MemVarPut Function
MemVarPutSym Function
MemVarRelease Function
MemWalk Function
MemWord Function
MethodList Function
MethodListClass Function
MExec Function
Min Function
MLCount Function
MLcToPos Function
MLPos Function
Month Function
MParamCount Function
MPosToLc Function
NewIndexLock Function
NewLocks Function
NoMethod Function
NTrim Function
Object2Array Function
Object2Float Function
Oem2AnsiBuff Function
OOPTree Function
OOPTreeClass Function
OrdBagExt Function
OrdBagName Function
OrdCondSet Function
OrdCount Function
OrdCreate Function
OrdDescend Function
OrdDestroy Function
OrdFor Function
OrdIsUnique Function
OrdKey Function
OrdKeyAdd Function
OrdKeyCount Function
OrdKeyDel Function
OrdKeyGoto Function
OrdKeyNo Function
OrdKeyVal Function
OrdList Function
OrdListAdd Function
OrdListClear Function
OrdListRebuild Function
OrdName Function
OrdNumber Function
OrdScope Function
OrdSetFocus Function
OrdSetRelation Function
OrdSkipUnique Function
Pad Function
PadC Function
PadL Function
PadR Function
PaletteRGB Function
Pause Function
PI Function
Pow Function
Psz2String Function
Psz2Usual Function
PszAlloc Function
PszLen Function
QOut Function
QQOut Function
Rand Function
RddCount Function
RddInfo Function
RddList Function
RddName Function
RddSetDefault Function
RddVersion Function
RecCount Function
RecNo Function
RecSize Function
RegisterAxit Function
RLock Function
Round Function
Row Function
RToD Function
Select Function
Send Function
Set Function
SetFDateTime Function
SetFloatDelta Function
SetPos Function
SEval Function
SEvalA Function
ShowArray Function
ShowObject Function
ShowPrivates Function
ShowPublics Function
Sin Function
SplitPath Function
SQrt Function
SToD Function
Str Function
Str1 Function
Str2 Function
Str3 Function
StrEvaluate Function
StrFloat Function
String2Atom Function
String2Symbol Function
StringAlloc Function
StrInt Function
StrLong Function
StrToFloat Function
StrTran Function
StrZero Function
SubS Function
SubStr Function
Symbol2String Function
SysAddAtom Function
SysAddAtomUpperA Function
SysCompAtom Function
SysFindAtom Function
SysGetAtomName Function
Tan Function
TimePsz Function
TimePsz24 Function
Today Function
Tone Function
ToWord Function
Transform Function
TString Function
Type Function
Unformat Function
UnRegisterAxit Function
Used Function
UsualType Function
UsualVal Function
Val Function
ValType Function
VarGet Function
VarGetSym Function
VarPut Function
VarPutSym Function
Version Function
VoDbAlias Function
VoDbAliasSym Function
VoDbAppend Function
VoDbBlobInfo Function
VoDbBof Function
VoDbBuffRefresh Function
VoDbClearFilter Function
VoDbClearLocate Function
VoDbClearRelation Function
VoDbClearScope Function
VoDbCloseAll Function
VoDbCloseArea Function
VoDbCommit Function
VoDbCommitAll Function
VoDbContinue Function
VoDbCreate Function
VoDbDelete Function
VoDbDeleted Function
VoDbEof Function
VoDbEval Function
VoDbFieldGet Function
VoDbFieldGetBytes Function
VoDbFieldInfo Function
VoDbFieldPut Function
VoDbFieldPutBytes Function
VoDbFileGet Function
VoDbFilePut Function
VoDbFilter Function
VoDbFlock Function
VoDbFound Function
VoDbGetScope Function
VoDbGetSelect Function
VoDbGoBottom Function
VoDbGoto Function
VoDbGoTop Function
VoDbInfo Function
VoDbJoinAppend Function
VoDbLastRec Function
VoDbLocate Function
VoDbMemoExt Function
VoDbOrdBagExt Function
VoDbOrdCondSet Function
VoDbOrdCreate Function
VoDbOrdDestroy Function
VoDbOrderInfo Function
VoDbOrdListAdd Function
VoDbOrdListClear Function
VoDbOrdListRebuild Function
VoDbOrdSetFocus Function
VoDbPack Function
VoDbRddCount Function
VoDbRddInfo Function
VoDbRddList Function
VoDbRddName Function
VoDbRddSetDefault Function
VoDbRecall Function
VoDbRecno Function
VoDbRecordGet Function
VoDbRecordInfo Function
VoDbRecordPut Function
VoDbRelation Function
VoDbRlock Function
VoDbRSelect Function
VoDbSeek Function
VoDbSelect Function
VoDbSetFilter Function
VoDbSetFound Function
VoDbSetLocate Function
VoDbSetRelation Function
VoDbSetScope Function
VoDbSetSelect Function
VoDbSkip Function
VoDbSkipScope Function
VoDbSort Function
VoDbSymSelect Function
VoDbTrans Function
VoDbTransRec Function
VoDbUnlock Function
VoDbUnLockAll Function
VoDbUseArea Function
VoDbZap Function
XSharpLoadLibrary Function
Year Function
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Default Function

Assign a default value to a NIL argument.

Namespace:  XSharp.RT
Assembly:  XSharp.RT (in XSharp.RT.dll) Version: 2.6
Syntax
Copy
 FUNCTION Default(
	uVar REF USUAL,
	uDefault AS USUAL
) AS VOID
Request Example View Source

Parameters

uVar
Type: Usual
The variable to which the default value will be assigned.  <uVar> must be passed by reference to the Default() function.
uDefault
Type: Usual
The default value to assign.

Return Value

Type: 
Remarks
Default() assigns <uDefault> to <uVar> if <uVar> is equal to NIL.
It is functionally equivalent to either of these code samples:
X#
Copy
1IF uVar = NIL
2    uVar := uDefault
3ENDIF
4IF IsNil(uVar)
5    uVar := uDefault
6ENDIF
Instead of Default(@<uVar>, 0), you could use EnforceNumeric(@<uVar>), which, besides checking <uVar> against NIL, calls the error system if <uVar> is neither numeric nor NIL.  You could also use EnforceType() whenever <uDefault> is the empty value (EmptyUsual()) for its data type; this raises an error if <uVar> is not a specific data type.
Therefore, instead of calling Default(@<uVar>, NULL_STRING), you could call EnforceType(@<uVar>, STRING).
Examples
This example uses Default() to check all parameters in a function:
X#
Copy
 1FUNCTION Start()
 2    LOCAL cCA1, cCA2
 3    LOCAL nScore
 4    LOCAL dDate
 5    cCA1 := "CA"
 6    cCA2 := "California"
 7    // nScore and dDate are NIL
 8    CheckArgs(cCA1, nScore, cCA2, dDate)
 9    RETURN TRUE
10FUNCTION CheckArgs(uOne, uTwo, uThree, uFour)
11    Default(@uOne, "CA-VO")
12    // NIL argument is assigned a value:
13    Default(@uTwo, 0)
14    Default(@uThree, NULL_STRING)
15    // NIL argument is assigned a value:
16    Default(@uFour, 0.0.0)
17    RETURN TRUE
Instead of using CheckArgs(), the following example, besides checking for NIL, checks for the correct data types and raises an error if incorrect types are passed:
X#
Copy
1FUNCTION CheckArgs2(uOne, uTwo, uThree, uFour)
2    Default(@uOne, "CA-VO")
3    EnforceNumeric(@uTwo)
4    EnforceType(@uThree, STRING)
5    EnforceType(@uFour, DATE)
6    RETURN TRUE
See Also