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qdosmsq:traps:trap_3:flin [2009/02/22 11:22]
george.gwilt created
qdosmsq:traps:trap_3:flin [2018/10/19 13:10]
norman [Example] Added example IO_FSTRG
Line 1: Line 1:
 +These traps read a set of bytes from a channel.
 +^Call Parameters^^Return Parameters^^
 +|D0.B|$02 or $03|D0.L|Error code.|
 +|D1.L| |D1.W|Number of bytes fetched.|
 +|D2.W|Length of buffer. |D2.L|Preserved.|
 +|A0.L|Channel ID |A0.L|Preserved.|
 +|A1.L|Pointer to buffer.|A1.L|Pointer to one byte after the last fetched.|
 +===== Errors =====
 +|ERR_NC|Not complete.|
 +|ERR_NO|Channel not open.|
 +|ERR_EF|End of file.|
 +|ERR_BO|Buffer overflow.|
 +===== Notes =====
 +  * All registers not shown above are not used on entry and are preserved on exit.
 +  * D0.B is $02 for IO_FLINE/IOB_FLIN and $03 for IO_FSTRG/IOB_FMUL.
 +  * IO_FLINE/IOB_FLIN fetches a line of bytes ending with LF ($0A). The LF is included as the last character fetched. If the number of bytes read before LF is reached exceeds the size of the buffer a buffer overflow error occurs.
 +  * IO_FSTRG/IOB_FMUL reads the number of bytes specified in D2.W unless EOF is reached first.
 +  * If bytes are being read from a CON channel the actions of the two Traps are different. For IO_FLINE/IOB_FLIN the cursor is enabled and the characters are mirrored in the window. Also the arrow keys can be used to edit the line in the normal way. For IO_FSTRG/IOB_FMUL the characters are not printed in the window and any cursor handling is up to the application.
 +===== Example =====
 +input   moveq   #io_fstrg,d0
 +        moveq   1024,d2                 ; Buffer max size
 +        moveq   #-1,d3                  ; Infinite timeout
 +        lea     input_buffer,a1         ; Read data into here
 +        move.l  a1,-(a7)                ; Save buffer address
 +        trap    #2
 +        cmpi.w  #ERR_EF,d0              ; EOF?
 +        beq.s   input_end               ; Yes
 +        tst.w   d0                      ; Any other error?
 +        bne.s   input_end               ; Yes
 +        move.l  (a7)+,a1                ; Restore buffer
 +        rts                             ; D0 = error code, ERR_EF or zero
 +        ds.w    1
 +        ds.b    1024
  • qdosmsq/traps/trap_3/flin.txt
  • Last modified: 2018/10/19 13:10
  • by norman