'===========================================================================
' Subject: READ INPUT FROM STDIN             Date: 02-06-97 (14:04)       
' Author:  Dave Navarro, Jr.                 Code: PB                     
' Origin:  dave@powerbasic.com             Packet: DOS.ABC
'===========================================================================
'===========================================================================
'
' Source Snippet (DOS): PowerBASIC 3.x
'
' Read input from STDIN
' by Dave Navarro, Jr.
'
' This example will will display a text file which is redirected to it.
'
' Example:  STDIN < c:\autoexec.bat
'
'===========================================================================

$LIB IPRINT ON
DEFINT A-Z

Ch = StdIn
WHILE Ch > 0
  IF Ch <> 10 THEN   'ignore line-feeds
    PRINT CHR$(Ch);
  END IF
  Ch = StdIn
WEND


'===========================================================================
' StdIn - Read a char from STDIN and return its ASCII value.  If it's an
'         extended keycode, it's returned as a negative value.
'
' Note:  Great for reading information which is redirected from a file.
'
FUNCTION StdIn() PUBLIC AS INTEGER

  ! push    DS                      ;

  ! mov     AH, &H0B                ; DOS function 0Bh, check STDIN
  ! int     &H21                    ; call DOS
  ! cmp     AL, &HFF                ; FFh if char is available
  ! je      ReadChar                ; yes, get it
  ! xor     AX, AX                  ; clear AX
  ! jmp     Done                    ; yes, no character ready so exit
ReadChar:
  ! mov     AH, &H07                ; DOS function 07h, get char from
STDIN
  ! int     &H21                    ; call DOS
  ! xor     AH, AH                  ; clear AH
  ! or      AL, AL                  ; was char a zero?  (extended key)
  ! jnz     Done                    ; no, exit

  ! mov     AH, &H07                ; DOS function 07h, get char from
STDIN
  ! int     &H21                    ; call DOS
  ! xor     AH, AH                  ; clear AH
  ! neg     AX                      ; make it negative
Done:
  ! pop     DS
  ! mov     FUNCTION, AX

END FUNCTION