FileOpen 及相關檔案讀寫

try
//打開一個特定的檔案并傳回檔案句柄
iFileHandle := FileOpen('d:\file.txt', fmOpenRead);
//傳回檔案共多少個字元
iFileLength := FileSeek(iFileHandle,1,0);

//指針指向檔案開頭
FileSeek(iFileHandle,0,0);
Buffer := PChar(AllocMem(iFileLength + 1));
//讀取第三個參數的大小到記憶體Buffer，傳回讀取幾個字元
iBytesRead := FileRead(iFileHandle, Buffer^, iFileLength+1);
//關閉檔案
FileClose(iFileHandle);
           

function FileOpen(const FileName: string; Mode: LongWord): Integer;

函數變量Mode的取值：

fmCreate If the file exists, open for write access, otherwise, create a new file. Unlike the other constants, which are declared in the SysUtils unit, this constant is declared in tge classes unit.

fmOpenRead Open for read access only.

fmOpenWrite Open for write access only.

fmOpenReadWrite Open for read and write access.

fmShareCompat Compatible with the way FCBs are opened. Do not use this mode in cross-platform applications.

fmShareExclusive Read and write access is denied.

fmShareDenyWrite Write access is denied.

fmShareDenyRead Read access is denied. Do not use this mode in cross-platform applications.

fmShareDenyNone Allows full access for others.

function FileSeek(Handle, Offset, Origin: Integer): Integer; overload;

變量Origin的取值：

0 The file pointer is positioned Offset bytes from the beginning of the file.

1 The file pointer is positioned Offset bytes from its current position.

2 The file pointer is positioned Offset bytes from the end of the file.

配置設定記憶體

function AllocMem(Size: Cardinal): Pointer;