N: SIO Command Change Directory ($2C)

This is a command for Devices $71-$78 - The N: Device (see SIO-Commands-for-Device-IDs-$71-to-$78).

Description

Sets the PREFIX of the selected N: device. This is a string that is pre-pended to any devicespec sent to e.g. OPEN or SPECIAL commands.

So if PREFIX was set to

HTTP://35.239.67.240/

then an OPEN call containing

N:BURIEDBU.COM

would be translated to:

N:HTTP://35.239.67.240/BURIEDBU.COM

It is possible to clear the prefix by sending either a completely zeroed buffer, or a buffer containing a single EOL ($9B)

Parameters

DCB	Value
DDEVIC	$71
DUNIT	$01 - $04
DCOMND	$FE
DSTATS	$80
DBUF	NULL
DTIMLO	$0F
DBYT	256
DAUX1	Any AUX1 bits to OR
DAUX2	Any AUX2 bits to OR

Examples

Atari BASIC

REM Change Directory (CMD 44 'CHDIR')
XIO 44,#1,0,0,"N:SUBDIR"

CC65

void nprefix(void)
{
  int i;

  OS.dcb.ddevic=0x71;
  OS.dcb.dunit=1;
  OS.dcb.dcomnd=0xFE;
  OS.dcb.dstats=0x80;
  OS.dcb.dbuf=&buf;
  OS.dcb.dtimlo=0x1f;
  OS.dcb.dbyt=256;
  OS.dcb.daux1=daux1;
  OS.dcb.daux2=daux2;
  siov();

  if (OS.dcb.dstats!=1)
    {
      err_sio();
      exit(OS.dcb.dstats);
    }
}