Keywords: pame

# Non-canonical input

The `noncanon` program provides a means of entering data via the keyboard without echoing it to the screen. This is known as non-canonical input mode, the usual echoing of input being canonical input mode. The general details of terminal control are very complex, but simple access has been provided with the `kbd channel`.

Here is a sample program which may be used to test the effect of `kbd channel`:

       PROGRAM noncanon CONTEXT VOID
       USE standard
       BEGIN
          STRING password;
          FILE kbd;  open(kbd,"",kbd channel);
          WHILE
             CHAR ch;  get bin(kbd,ch);
             ch /= REPR lf
          DO
             password+:=ch;
             print("*")
          OD;
          close(kbd);
          print(("You entered [",
                 password,"]",
                 newline))
       END
       FINISH

Notice that the program cannot be aborted by pressing `^C`. Ensure you close the `FILE` opened with the `kbd channel` after use otherwise you'll find all your commands at the command prompt unechoed. If that happens, issue the following command at the prompt:

       $ stty sane

when normal echoing will be restored.