asked on

write a array of char to file

I have a TBuf as array of char and I want to write it to a file without loosing any data(if i write it as string i loose some of the data)

Does anyone know which function to use or how to do it.

Tom

StevenB

You'll probably want to use the TFileStream object, specifically the WriteBuffer method. I'll write you an example when I get a spare minute :o)

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TheRealLoki

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StevenB

Something along these lines should do the trick:

const
aCharArray : array[1..10] of Char = ('a','b','c','d','e','f','g','h','i','j');
var
aFileStream : TFileStream;
aCharArrayLength : Integer;
begin
aFileStream := TFileStream.Create('C:\Temp\TempFile.dat', fmCreate);
try
aCharArrayLength := SizeOf(aCharArray);
aFileStream.WriteBuffer(aCharArray, aCharArrayLength);
finally
FreeAndNil(aFileStream);
end;
end;

StevenB

Sorry, didn't refresh, missed that example.

jturpin

If you use a PChar you would have to say:

fs.Write(mypchar^, buffersize);

John.

ZhaawZ

I'd use untyped file to write.

var
f : file;
buff : array of char;
begin
assignfile(f, 'file.txt');
rewrite(f, 1);
blockwrite(f, buff[0], length(buff));
closefile(f);
end;

T0masz

ASKER

I want to be able to use type TBuf as array of char...

T0masz

ASKER

function fread2(var SomeFile: File; n : integer) : TBuf; //declared as TBuf = array of char; in the interface section
var nread : integer;
begin
try
SetLength(result, n);
Reset(SomeFile, 1);
BlockRead(SomeFile, result, n, nread);
CloseFile(SomeFile);
// raise exception.Create('Could not read requested number of bytes.'#13'-Only '+IntToStr(nRead)+' bytes were read');
Setlength(result, nRead);
except on e: exception do
raise exception.Create('Error reading from file:'#13+e.Message);
end;
end;

T0masz

ASKER

buff := fread2(f, strtoint(ar['TiffPage1_image_size'])); // buff as type TBuf as array of char..
assignfile(f, 'c:\test2.tif');
rewrite(f, 1);
blockwrite(f, buff[0], length(buff));
closefile(f);

I get access violation on assignfile

T0masz

ASKER

oops fread2(f1,strtoint...... ) but even with that fixed I still get the same error.

ZhaawZ

BlockRead(SomeFile, result, n, nread);

try to use result[0] instead of result

TheRealLoki

did you try the filestream method i posted above?

StevenB

*sigh*