Title: How to open a Delphi text file fmShareDenyNone?
Question: Delphis system.filemode variable controls only the mode of binary files. For text files this variable is ignored. I wanted to open a file in text mode even an other process keeps it open for writing (unless it denies read), but I did not want to alter the assembler code in the VCL.
Answer:
// Important: The following code was only tested with Delphi 5
Implementation
Uses
Windows, SysUtils, SysConst;
procedure OpenReadText(var f:Text;SwitchIminus:Boolean);
// Opening a text file that might be open for write
// Input
// f: a text file that was prepared with AssignFile
// SwitchIminus: set true if you want {$-} style processing,
// with no exceptions
begin
try
// try the standard way i.e. generic_read, file_share_read
// this is important to further prepare the TextRect items
// If the file is not open for write, its done, we need reset
// to assign the imput function to TTextRec(f).InoutFunc
Reset(f);
except
with TTextRec(f) do begin
// else we try generic_read, file_share_read or file_share_write
handle:=FileOpen(Name,fmShareDenyNone);
if dword(handle)=invalid_handle_value then begin
if SwitchIminus then
SetInOutRes(GetLastError)
else
raise EInOutError.CreateResFmt(@SInOutError, [GetLastError]);
end;
mode:=fmInput;
BufPos:=0;
BufEnd:=0;
end;
end;
end{OpenReadText};