Move file offset to end when file_base::append is specified.

chriskohlhoff · Apr 2, 2024 · 6fca427 · 6fca427
1 parent 7038ebd
commit 6fca427
Showing 1 changed file with 22 additions and 7 deletions.
diff --git a/asio/include/asio/detail/impl/win_iocp_file_service.ipp b/asio/include/asio/detail/impl/win_iocp_file_service.ipp
@@ -97,15 +97,30 @@ asio::error_code win_iocp_file_service::open(
  HANDLE handle = ::CreateFileA(path, access, share, 0, disposition, flags, 0);
  if (handle != INVALID_HANDLE_VALUE)
  {
- if (disposition == OPEN_ALWAYS && (open_flags & file_base::truncate) != 0)
+ if (disposition == OPEN_ALWAYS)
  {
- if (!::SetEndOfFile(handle))
+ if ((open_flags & file_base::truncate) != 0)
  {
- DWORD last_error = ::GetLastError();
- ::CloseHandle(handle);
- ec.assign(last_error, asio::error::get_system_category());
- ASIO_ERROR_LOCATION(ec);
- return ec;
+ if (!::SetEndOfFile(handle))
+ {
+ DWORD last_error = ::GetLastError();
+ ::CloseHandle(handle);
+ ec.assign(last_error, asio::error::get_system_category());
+ ASIO_ERROR_LOCATION(ec);
+ return ec;
+ }
+ }
+ else if ((open_flags & file_base::append) != 0)
+ {
+ if (::SetFilePointer(handle, 0, 0, FILE_END)
+ == INVALID_SET_FILE_POINTER)
+ {
+ DWORD last_error = ::GetLastError();
+ ::CloseHandle(handle);
+ ec.assign(last_error, asio::error::get_system_category());
+ ASIO_ERROR_LOCATION(ec);
+ return ec;
+ }
  }
  }