exists()

bool xtd::io::file_info::exists ( ) const

overridevirtual

Gets a value indicating whether a file exists.

Returns

true if the file exists; false if the file does not exist or if the file is a directory.

Examples

The following code example uses the xtd::io::file_info::exists property ensure a file exists before opening it. You can use this technique to throw a custom exception when the file is not found.

std::vector<char> open_data_file(const string& file_name) {
  // Check the FileName argument.
  if (file_name.size() == 0)
    throw argument_exception("file_name", csf_);
 
  // Check to see if the file exists.
  file_info f_info(file_name);
 
  // You can throw a personalized exception if
  // the file does not exist.
  if (!f_info.exists())
    throw file_not_found_exception("The file was not found.", csf_);
 
  // Open the file.
  std::ifstream f_stream(file_name, std::ios::binary);
 
  // Create a buffer.
  std::vector<char> buffer(f_info.size());
 
  // Read the file contents to the buffer.
  f_stream.read(&buffer[0], f_info.size());
 
  // return the buffer.
  return buffer;
}

Remarks

When first called, xtd::io::file_info calls xtd::io::file_info::refresh and caches information about the file. On subsequent calls, you must call xtd::io::file_info::refresh to get the latest copy of the information.

The xtd::io::file_info::exists property returns false if any error occurs while trying to determine if the specified file exists. This can occur in situations that raise exceptions such as passing a file name with invalid characters or too many characters, a failing or missing disk, or if the caller does not have permission to read the file.

Implements xtd::io::file_system_info.

Examples

file_info2.cpp, and file_info_move_to.cpp.