Accessing a single file with multiple threads

Question

I need to access a file concurrently with multiple threads. This needs to be done concurrently, without thread serialisation for performance reasons.

The file in par

Answer 1

You can do on that way...

First thread with read/write access must at first create file:

FileHandle := CreateFile(
  PChar(FileName),
  GENERIC_READ or GENERIC_WRITE,
  FILE_SHARE_READ,
  nil,
  CREATE_ALWAYS,
  FILE_ATTRIBUTE_NORMAL,
  0);

Sencond thread with only read access then opens the same file:

  FileHandle := CreateFile(
    PCHar(FileName),
    GENERIC_READ,
    FILE_SHARE_READ + FILE_SHARE_WRITE,
    nil,
    OPEN_EXISTING,
    FILE_ATTRIBUTE_NORMAL,
    0);

I didn't test if works with...

FILE_ATTRIBUTE_TEMPORARY,
FILE_FLAG_DELETE_ON_CLOSE

attributes...