by Richard Russell, July 2006

On the BBC Microcomputer and some other Acorn computers you could insert a character into the keyboard buffer using the *FX 138 command. For example the following code would insert the character “R” (CHR$82) into the keyboard buffer:

      *FX138,0,82

BBC BASIC for Windows doesn't have a directly equivalent command, but you can achieve the same effect using the following procedure:

      DEF PROCfx138(C%)
      WM_CHAR = 258
      SYS "PostMessage", @hwnd%, WM_CHAR, C%, 0
      ENDPROC

The equivalent procedure for BBC BASIC for SDL 2.0 is as follows:

      DEF PROCfx138(C%)
      LOCAL ev{} : DIM ev{type%,stamp%,winid%,text&(1)}
      ev.type% = &303 : ev.text&(0) = C% : SYS "SDL_PushEvent", ev{}
      ENDPROC

So to insert the character “R” into the keyboard buffer you would do:

      PROCfx138(82)

or, equivalently,

      PROCfx138(ASC("R"))