On Mon, Jan 07, 2013 at 03:09:31PM +0000, Andrew Haley wrote:
> On 01/07/2013 05:11 AM, horseriver wrote:
> > On Mon, Jan 07, 2013 at 02:31:19PM +0000, Andrew Haley wrote:
> >> On 01/07/2013 04:46 AM, horseriver wrote:
> >>> hi:
> >>>
> >>> how to implement this assignment by MACRO?
> >>> int a,b,c ;
> >>>
> >>> ((a==0)?b:c)=8;
> >>
> >> This is for help with GCC, not general C coding help.
> >>
> >> *((a==0) ? &b : &c) = 8;
> >>
> >> But this is really horrible code. I wouldn't do it.
> >
> > thans!
> >
> > why gcc report that error ?
> >
> > gcc can translate " ((a==0)?b:c)=8 " into if-else sentence .
> >
> > wht is the reason ？
>
> Please supply the test case and the error message.
>
ok
here is this code :
#define INPUT_KEYCODE(dev, scancode) ((dev->keycodesize == 1) ? ((u8*)dev->keycode)[scancode] : \
((dev->keycodesize == 2) ? ((u16*)dev->keycode)[scancode] : (((u32*)dev->keycode)[scancode])))
and here is the callee code :
unsigned int keycode ;
INPUT_KEYCODE(dev, scancode) = keycode;
dev is a struct , scancode is a unsigned int
and gcc report error is :
error: lvalue required as left operand of assignment
thanks!
> Andrew.
>
>
