last_write_time() [2/2]

xtd::io::file_system_info & xtd::io::file_system_info::last_write_time

(

const xtd::date_time &

value

)

Sets the time when the current file or directory was last written to.

Parameters

value

The time the current file was last written.

Exceptions

xtd::io::io_exception	system error when retrieving the file information.
xtd::io::directory_not_found_exception	The specified path is invalid; for example, it is on an unmapped drive.
xtd::platform_not_supported_exception	The opration is not supported on the current operating system.

Examples

The following code example demonstrates the updating of the xtd::io::file_system_info::last_write_time property through a "touch" operation. In this example, the file is "touched", updating the xtd::io::file_system_info::creation_time, xtd::io::file_system_info::last_access_time and xtd::io::file_system_info::last_write_time properties to the current date and time.

#include <xtd/xtd>
 
using namespace xtd;
using namespace xtd::io;
 
class touch {
public:
  static auto main(const std::vector<string>& args) {
    // Make sure a filename was provided.
    if (args.size() > 0) {
      // Verify that the provided filename exists.
      if (file::exists(args[0])) {
        file_info fi(args[0]);
        touch_file(fi);
      } else {
        console::write_line("Could not find the file: {0}.", args[0]);
      }
    } else {
      console::write_line("No file was specified.");
    }
  }
 
  static void touch_file(file_system_info& fsi) {
    console::write_line("Touching: {0}", fsi.full_name());
 
    // Update the CreationTime, LastWriteTime and LastAccessTime.
    try {
      auto now = date_time::now();
      fsi.creation_time(now).last_write_time(now).last_access_time(now);
    } catch (const exception& e) {
      console::write_line("Error: {0}", e.message());
    }
  }
};
 
startup_(touch::main);

Note

This method may set an inaccurate value because it uses native functions whose values may not be continuously updated by the operating system.

Remarks

The value of the xtd::io::file_system_info::last_write_time property is pre-cached if the current instance of the xtd::io::file_system_info object was returned from any of the following xtd::io::directory_info methods:

• xtd::io::directory_info::get_directories
• xtd::io::directory_info::get_files
• xtd::io::directory_info::get_file_system_infos
• xtd::io::directory_info::enumerate_directories
• xtd::io::directory_info::enumerate_files
• xtd::io::directory_info::enumerate_file_system_infos
• To get the latest value, call the xtd::io::file_system_info::refresh method.