Oh sorry, That was a blunder mishap. My extreme apologies for this. I literally ignored the define statement which were defined earlier. Regards, Mukund Jampala >-----Original Message----- >From: Abu M. Muttalib [mailto:abum@xxxxxxxxx] >Sent: Saturday, February 18, 2006 7:40 AM >To: Mukund JB.; kernelnewbies >Cc: Fawad Lateef >Subject: RE: MACRO - How is it working in Linux > >Hi, > >Pls find below the CPP processed source code. I hope you can then make out >how does it work. > >main() >{ > int abc = (1 = 2); > printf("abc = %d\n",abc); >} > >~Abu. > >Abu M. Muttalib >Sr. Engineer, Embedded System, >Aftek Infosys Ltd., >Office: 91-20-25449260-65 X-256 >Mobile: (0)9881322820 >Email: abum@xxxxxxxxx > > >-----Original Message----- >From: kernelnewbies-bounce@xxxxxxxxxxxx >[mailto:kernelnewbies-bounce@xxxxxxxxxxxx]On Behalf Of Mukund JB. >Sent: Friday, February 17, 2006 7:02 PM >To: kernelnewbies >Cc: Fawad Lateef >Subject: MACRO - How is it working in Linux > > >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? > >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/
