Question

With following code i write an

  dest : array of Bytes;

to a file.

  c: integer;
  size: integer;

If i do it Byte by Byte:

  filename := ExePath + 'test.txt';
  AssignFile(myfile, filename);
  ReWrite(myfile, 1);
  Write the data array to the file
  for c := 0 to length(dest) - 1 do
     BlockWrite(myfile, dest[c], 1);
  CloseFile(myfile);

everything works fine, but takes ages on large arrays (20MB biggest).

If i try to write it @ once i get I/O Error 1784:

  filename := ExePath + 'test.txt';
  AssignFile(myfile, filename);
  size := length(dest);
  ReWrite(myfile, size);
  BlockWrite(myfile, dest[0], size);
  CloseFile(myfile);

Where is may fault?
Thanks in advance.

Answer 1

Got it…

@ myself: RTFM

BlockWrite(myfile, dest[0], size);

must be

BlockWrite(myfile, dest[0], 1);

cause size is defined already to the size of the array with rewrite….

filename := ExePath + 'test.txt';
AssignFile(myfile, filename);
size := length(dest);
ReWrite(myfile, size);
BlockWrite(myfile, dest[0], 1);   <-- 1 "dataset" of length (size) as defined before
CloseFile(myfile);