TSetRslBlk
#include <PrintTraps.h>
typedef struct TSetRslBlk { Size Offset Description short iOpCode; 2 0 4 = opcode for SetRsl
short iError ; 2 2 0=noErr; 1=noSuchRsl;
2=opNotImpl
long lReserved; 4 4 (not used )
short iXRsl; 2 12 Requested X-axis resolution
short iYRsl; 2 14 Requested Y-axis resolution
and, in fact, constitute the TGnlData record. HPrint is the handle to a succeeds, TPrint is updated with the resolution requested in iXRsl and iYRsl, a 0=noErr is returned. If the request can't be satisfied, an error
code is returned (1=noSuchRsl) and the resolution fields take the values of
the printer's default resolution
(default = 0 x 0 ).
Purposely specifying an invalid resolution can be used to undo the effect of
a previous PrGeneral call since the effect will be to force the printer back to its default.