On 2/17/06, Mukund JB. <mukundjb@xxxxxxxxxxxxxxxxxxxxx> wrote:
> Dear All,
>
> I have seen a macro like this in the Linux kernel sources in
> include/linux/usb.h line no: 1090.
>
> #define usb_dotoggle(dev, ep, out) ((dev)->toggle[out] ^= (1 << (ep)))
>
> I did not understand how it works?
> I have written a small usermode program to test this.
>
> #define x 1
> #define y 2
> #define macro() (x = y)
> main()
> {
> int abc = macro();
> printf("abc = %d\n",abc);
> }
>
> This code results in a compile error.
> test.c:9: error: invalid lvalue in assignment.
>
> Why?
do u think 1=2 is a valid statement?
>
> Regards,
> Mukund Jampala
>
>
> --
> Kernelnewbies: Help each other learn about the Linux kernel.
> Archive: http://mail.nl.linux.org/kernelnewbies/
> FAQ: http://kernelnewbies.org/faq/
>
>
--
Kernelnewbies: Help each other learn about the Linux kernel.
Archive: http://mail.nl.linux.org/kernelnewbies/
FAQ: http://kernelnewbies.org/faq/
