GN_Del, delete a file from memory

RST 20H, DEFW $6409

IN:

     HL = 0,1,2; not allowed (B=0)
     BHL = extended pointer to filename. HL must be > 255
     (B = 0 -> HL is local pointer)

     Fc = 0

     Fc = 1
     A = error code:
          RC_ONF ($12), file not found
          RC_IVF ($17), invalid filename
          RC_USE ($15), file is in use, ie. not closed

     ..BCDEHL/IXIY same
     AF....../.... different

The filename must be terminated by a control character, eg. null (0) or CR (13).

Related calls:

GN_Cl, close file
GN_Opf, open file/resource (wildcard search)
GN_Ren, rename file OS_Cl, internal close (OZ usage)
OS_Del, file delete (internal OZ usage)
OS_Frm, file read miscellaneous
OS_Fwm, file write miscellaneous
OS_Gb, get byte from file (or device)
OS_Gbt, get byte from file (or device) with timeout
OS_Mv, move bytes between stream and memory
OS_Op, internal open (OZ usage)
OS_Pb, write byte to file, device
OS_Pbt, write byte to file, device with timeout
OS_Ren, file rename (internal OZ usage)