redirect_standard_input() [2/2]

process_start_info & xtd::diagnostics::process_start_info::redirect_standard_input ( bool  value )

noexcept

Sts a value indicating whether the input for an application is read from the Process.StandardInput stream.

Parameters

value

true if input should be read from Process.StandardInput; otherwise, false. The default is false.

Returns

The current instance of process_start_info.

Examples

The following example illustrates how to redirect the xtd::diagnostics::process::standard_input stream of a process. The example starts the sort command with redirected input. It then prompts the user for text, and passes that to the sort process by means of the redirected xtd::diagnostics::process::standard_input stream. The sort results are displayed to the user on the console.

#include <xtd/xtd>
 
using namespace xtd;
using namespace xtd::diagnostics;
using namespace xtd::io;
 
auto main() -> int {
  console::write_line("Ready to sort one or more text lines...");
 
  // Start the sort process with redirected input.
  // Use the sort command to sort the input text.
  block_scope_(process my_process) {
    my_process.start_info().file_name("sort");
    my_process.start_info().use_shell_execute(false);
    my_process.start_info().redirect_standard_input(true);
 
    my_process.start();
 
    stream_writer my_stream_writer(my_process.standard_input());
 
    // Prompt the user for input text lines to sort.
    // Write each line to the StandardInput stream of
    // the sort command.
    string input_text;
    int num_lines = 0;
    do {
      console::write_line("Enter a line of text (or press the Enter key to stop):");
 
      input_text = console::read_line();
      if (input_text.size() > 0) {
        num_lines++;
        my_stream_writer.write_line(input_text);
      }
    } while (input_text.size() > 0);
 
    // Write a report header to the console.
    if (num_lines > 0) {
      console::write_line(" {} sorted text line(s) ", num_lines);
      console::write_line("------------------------");
    } else {
      console::write_line(" No input was sorted");
    }
 
    // End the input stream to the sort command.
    // When the stream closes, the sort command
    // writes the sorted text lines to the
    // console.
    my_stream_writer.close();
 
    // Wait for the sort process to write the sorted text lines.
    my_process.wait_for_exit();
  }
}

Remarks

A xtd::diagnostics::process can read input text from its standard input stream, typically the keyboard. By redirecting the xtd::diagnostics::process::standard_input stream, you can programmatically specify the input. For example, instead of using keyboard input, you can provide text from the contents of a designated file or output from another application.

Note

To use xtd::diagnostics::process::standard_input, you must set xtd::diagnostics::process_start_info::use_shell_execute to false, and you must set xtd::diagnostics::process_start_info::redirect_standard_input to true. Otherwise, writing to the xtd::diagnostics::process::standard_input stream throws an exception.