_C2Hex Function (Core)

_DebOut32 Function (Core)

_GetCmdLine Function (Core)

_GetCmdShow Function (Core)

_GetInst Function (Core)

_GetPrevInst Function (Core)

_Like Function (Core)

_Quit Function (Core)

_SplitPath Function (Core)

_Val Function (Core)

AbsInt Function (Core)

AbsLong Function (Core)

AbsReal4 Function (Core)

AbsReal8 Function (Core)

AbsShort Function (Core)

AdjustFName Function (Core)

AdjustFNameA Function (Core)

AllTrim Function (Core)

AltD Function (Core)

AmPm Function (Core)

Ansi2Oem Function (Core)

Ansi2OemA Function (Core)

Ansi2OemBuff Function (Core)

ATCLine Function (Core)

ATCLine2 Function (Core)

ATLine Function (Core)

ATLine2 Function (Core)

B64EncFile Function (Core)

B64EncString Function (Core)

Bin2DW Function (Core)

Bin2I Function (Core)

Bin2L Function (Core)

Bin2Logic Function (Core)

Bin2Ptr Function (Core)

Bin2Real4 Function (Core)

Bin2Real8 Function (Core)

Bin2W Function (Core)

Buffer Function (Core)

C2Hex Function (Core)

CharEven Function (Core)

CharMix Function (Core)

CharOdd Function (Core)

CharPos Function (Core)

Chr Function (Core)

ChrA Function (Core)

ChrW Function (Core)

ConDateTime Function (Core)

ConTime Function (Core)

CToDt Function (Core)

CToDtAnsi Function (Core)

CTOL Function (Core)

CurDir Function (Core)

CurDrive Function (Core)

DateTime Function (Core)

Days Function (Core)

DbRegisterClient Function (Core)

DbUnRegisterClient Function (Core)

DebOut32 Function (Core)

DecodeBase64 Function (Core)

DirChange Function (Core)

DirMake Function (Core)

DirRemove Function (Core)

DiskChange Function (Core)

DiskFree Function (Core)

DiskName Function (Core)

DiskSpace Function (Core)

DosError Function (Core)

DosErrString Function (Core)

DtToC Function (Core)

DtToS Function (Core)

DW2Bin Function (Core)

ElapTime Function (Core)

EncodeBase64 Function (Core)

ErrorBuild Function (Core)

ErrorLevel Function (Core)

ErrorStack Function (Core)

ErrString Function (Core)

ExecName Function (Core)

FAttr2String Function (Core)

FAttrib Function (Core)

FChSize Function (Core)

FClose Function (Core)

FCommit Function (Core)

FConvertToFileStream Function (Core)

FConvertToMemoryStream Function (Core)

FCopy Function (Core)

FCreate Function (Core)

FCreate2 Function (Core)

FDate Function (Core)

FEof Function (Core)

FErase Function (Core)

FError Function (Core)

FException Function (Core)

FFCount Function (Core)

FFirst Function (Core)

FFLock Function (Core)

FFLock64 Function (Core)

FFlush Function (Core)

FFUnLock Function (Core)

FFUnLock64 Function (Core)

FGetBuffer Function (Core)

FGetFileName Function (Core)

FGetS Function (Core)

FGetS2 Function (Core)

FGetStream Function (Core)

File Function (Core)

FName Function (Core)

FNext Function (Core)

FOpen Function (Core)

FOpen2 Function (Core)

FPathName Function (Core)

FPutS Function (Core)

FPutS3 Function (Core)

FRead Function (Core)

FRead3 Function (Core)

FRead4 Function (Core)

FReadLine Function (Core)

FReadLine2 Function (Core)

FReadStr Function (Core)

FReadText Function (Core)

FReadText3 Function (Core)

FRename Function (Core)

FRewind Function (Core)

FSeek3 Function (Core)

FSize Function (Core)

FTell Function (Core)

FTell64 Function (Core)

FTime Function (Core)

FWrite Function (Core)

FWrite3 Function (Core)

FWrite4 Function (Core)

FWriteLine Function (Core)

FWriteLine3 Function (Core)

FWriteText3 Function (Core)

GetAMExt Function (Core)

GetAmPm Function (Core)

GetAnsi Function (Core)

GetChunkBase64 Function (Core)

GetCurPath Function (Core)

GetCursorProperty Function (Core)

GetDateFormat Function (Core)

GetDefault Function (Core)

GetDefaultDir Function (Core)

GetDosError Function (Core)

GetEnv Function (Core)

GetFAttr Function (Core)

GetFMask Function (Core)

GetMacroCompiler Function (Core)

GetMimType Function (Core)

GetNatDLL Function (Core)

GetPartialEnumName Function (Core)

GetPMExt Function (Core)

GetSQLProperty Function (Core)

GetTimeSep Function (Core)

GetTimeZoneDiff Function (Core)

GetYield Function (Core)

HardCR Function (Core)

Hex2C Function (Core)

HiByte Function (Core)

HiWord Function (Core)

I2Bin Function (Core)

Instr Function (Core)

IsAlNum Function (Core)

IsAlpha Function (Core)

IsAlphaNum Function (Core)

IsBDigit Function (Core)

IsDigit Function (Core)

IsLower Function (Core)

IsRunningOnWindows Function (Core)

IsSpace Function (Core)

IsUpper Function (Core)

IsXDigit Function (Core)

L2Bin Function (Core)

Left Function (Core)

Like Function (Core)

LoByte Function (Core)

LockTries Function (Core)

Logic2Bin Function (Core)

Lower Function (Core)

LowerA Function (Core)

LoWord Function (Core)

LTOC Function (Core)

LTrim Function (Core)

MakeDWord Function (Core)

MakeLong Function (Core)

MakeShort Function (Core)

MakeWord Function (Core)

MemLines Function (Core)

MemoLine Function (Core)

MemoRead Function (Core)

MemoReadBinary Function (Core)

MemoWrit Function (Core)

MemoWritBinary Function (Core)

MLCount1 Function (Core)

MLcToPos Function (Core)

MLine Function (Core)

MLine3 Function (Core)

MLPos2 Function (Core)

Mod Function (Core)

ModuleName Function (Core)

NetErr Function (Core)

NetName Function (Core)

NToCDoW Function (Core)

NToCMonth Function (Core)

Occurs Function (Core)

Occurs2 Function (Core)

Occurs3 Function (Core)

Oem2Ansi Function (Core)

Oem2AnsiA Function (Core)

Oem2AnsiBuff Function (Core)

OS Function (Core)

ProcFile Function (Core)

ProcLine Function (Core)

ProcName Function (Core)

Proper Function (Core)

ProperA Function (Core)

Ptr2Bin Function (Core)

QPEncString Function (Core)

RAt Function (Core)

RAt2 Function (Core)

RAt3 Function (Core)

RAtLine Function (Core)

RATLine2 Function (Core)

ReadOsVersionFromRegistry Function (Core)

Real42Bin Function (Core)

Real82Bin Function (Core)

RegisterFileSearch Function (Core)

Repl Function (Core)

Replicate Function (Core)

RGB Function (Core)

Right Function (Core)

RTrim Function (Core)

SClone Function (Core)

Seconds Function (Core)

Secs Function (Core)

SetAMExt Function (Core)

SetAmPm Function (Core)

SetAnsi Function (Core)

SetBeep Function (Core)

SetCentury Function (Core)

SetCollation Function (Core)

SetCompatible Function (Core)

SetCpu Function (Core)

SetDateCountry Function (Core)

SetDateFormat Function (Core)

SetDecimal Function (Core)

SetDecimalSep Function (Core)

SetDefault Function (Core)

SetDefaultDir Function (Core)

SetDeleted Function (Core)

SetDigit Function (Core)

SetDigitFixed Function (Core)

SetEnv Function (Core)

SetEpoch Function (Core)

SetErrorLog Function (Core)

SetErrorLogFile Function (Core)

SetErrorStackVOFormat Function (Core)

SetExact Function (Core)

SetExclusive Function (Core)

SetFieldStore Function (Core)

SetFixed Function (Core)

SetInternational Function (Core)

SetMacroCompiler Function (Core)

SetMacroDuplicatesResolver Function (Core)

SetMath Function (Core)

SetNatDLL Function (Core)

SetPath Function (Core)

SetPathArray Function (Core)

SetPMExt Function (Core)

SetRefresh Function (Core)

SetSafety Function (Core)

SetScience Function (Core)

SetSoftSeek Function (Core)

SetSpace Function (Core)

SetThousandSep Function (Core)

SetTimeFormat Function (Core)

SetTimeSep Function (Core)

SetUnique Function (Core)

SetYield Function (Core)

SLen Function (Core)

SoundEx Function (Core)

Space Function (Core)

SToDt Function (Core)

String2FAttr Function (Core)

Stuff Function (Core)

SubStr2 Function (Core)

SubStr3 Function (Core)

SwapByte Function (Core)

SwapDWord Function (Core)

SwapInt Function (Core)

SwapInt64 Function (Core)

SwapLong Function (Core)

SwapQWord Function (Core)

SwapShort Function (Core)

SwapWord Function (Core)

SystemTypeToUsualType Function (Core)

Time Function (Core)

Time24 Function (Core)

Trim Function (Core)

TruePath Function (Core)

TString Function (Core)

TypeString Function (Core)

Upper Function (Core)

UpperA Function (Core)

UseBufferedFileStream Function (Core)

UUDecodeLine Function (Core)

UUEncFile Function (Core)

UUEncLine Function (Core)

W2Bin Function (Core)

WorkDir Function (Core)

FFLock64 Function

Lock a portion of an open file.

Namespace: XSharp.Core
Assembly: XSharp.Core (in XSharp.Core.dll) Version: 2.19

Syntax

Copy

 FUNCTION FFLock64(
	ptrHandle AS IntPtr,
	offset AS INT64,
	length AS INT64
) AS LOGIC

public static bool FFLock64(
	IntPtr ptrHandle,
	long offset,
	long length
)

Request Example View Source

Parameters

ptrHandle: Type: IntPtr
The handle of the open file you want to lock.
offset: Type: Int64
The file offset at which to start locking.
A value of zero corresponds to the first byte of the file.
length: Type: Int64
The number of bytes to lock.

Return Value

Type: Logic
TRUE if successful; otherwise, FALSE.

Remarks

FFLock() locks a specified portion of a file.
This prevents other processes from accessing that portion. More than one portion of a file can be locked, but the same byte should not be locked more than once.
It is also possible to lock past the end of a file.
This allows you to append to a file in a multi-user environment.

Remarks

Tip
The low level File IO functions in the X# runtime are using .Net filestreams in the background. That means that the file handles returned by FOpen() and FCreate() are not 'normal' file handles, but unique identifiers that are used to find the underlying stream object in a collection of streams in the runtime. That also means that you can't use file handles for functions such as FRead() and FWrite() that were not created in the X# runtime. If you want to access the underlying FileStream, then you should call the function FGetStream(IntPtr)

Tip

The low level File IO functions in the X# runtime are using .Net filestreams in the background.
That means that the file handles returned by FOpen() and FCreate() are not 'normal' file handles, but unique identifiers that are used to find the underlying stream object in a collection of streams in the runtime.
That also means that you can't use file handles for functions such as FRead() and FWrite() that were not created in the X# runtime.
If you want to access the underlying FileStream, then you should call the function FGetStream(IntPtr)

Examples

This example uses FFLock() to lock 100 bytes of a file starting at offset 300:

Copy

1ptrHandle := FOpen2("c:\data\myfile.txt", ;
2        FO_READWRITE + FO_SHARED)
3IF FFLock(ptrHandle, 300, 100)
4    ? "Locked OK"
5ENDIF

This example implements an FFLock() with an optional retry:

Copy

 1FUNCTION FileLock(ptrHandle AS PTR,;
 2        dwOffset AS DWORD, dwLength AS DWORD,;
 3        wSeconds AS DWORD) AS LOGIC PASCAL
 4    LOCAL lForever AS LOGIC
 5    IF FFLock(ptrHandle, dwOffset, dwLength)
 6        RETURN TRUE            // Locked
 7    ENDIF
 8    // If wSeconds is zero, retry until successful
 9    lForever := (wSeconds = 0)
10    DO WHILE (lForever .OR. wSeconds > 0)
11        IF FFLock(ptrHandle, dwOffset, dwLength)
12            RETURN TRUE    // Locked
13        ENDIF
14        InKey(.5)            // Wait up
15        nSeconds -= 1
16    ENDDO
17    RETURN FALSE                // Not locked

Reference

Functions, Globals and Defines

XSharp.Core Namespace

FFUnLock64(IntPtr, Int64, Int64)

IndexHPLock(Usual)

NewIndexLock(Usual)