On Tue, Apr 10, 2007 at 06:45:32AM -0400, Robert P. J. Day wrote: > > from the gcc manual > (http://gcc.gnu.org/onlinedocs/gcc-4.1.2/gcc/Alternate-Keywords.html#Alternate-Keywords): > > "-ansi and the various -std options disable certain keywords. This > causes trouble when you want to use GNU C extensions, or a > general-purpose header file that should be usable by all programs, > including ISO C programs. The keywords asm, typeof and inline are not > available in programs compiled with -ansi or -std (although inline can > be used in a program compiled with -std=c99). The ISO C99 keyword > restrict is only available when -std=gnu99 (which will eventually be > the default) or -std=c99 (or the equivalent -std=iso9899:1999) is > used." > > "The way to solve these problems is to put `__' at the beginning and > end of each problematical keyword. For example, use __asm__ instead of > asm, and __inline__ instead of inline. " > > what this tells me (and CMIIW) is that one need only use the "__" > variations in kernel source that is being exported to userspace, yes? > that is, in the same way that using "__u32" instead of just "u32" is > only *necessary* under the same circumstances. For userspace, the problem is not restricted to keywords. Userspace that indirectly #include's kernel headers might already use the same name for something completely different. > so while it's not, technically speaking, *wrong*, it's not necessary > to have used that longer variation in, say, net/packet/af_packet.c: > > #define XC(a, b) ({ __typeof__ ((a)) __t; __t = (a); (a) = (b); __t; > }) > > since that's a source file and there's no way that would have made it > to userspace anyway. do i understand that correctly? #define's are a different but related problem: "t" is a valid variable name, and there could be a variable "t" in kernel code using XC(). > rday cu Adrian -- "Is there not promise of rain?" Ling Tan asked suddenly out of the darkness. There had been need of rain for many days. "Only a promise," Lao Er said. Pearl S. Buck - Dragon Seed -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
