On Tue, Aug 28, 2012 at 06:23:38PM +0100, Peter Maydell wrote: > On 28 August 2012 18:18, Michael S. Tsirkin <m...@redhat.com> wrote: > > On Tue, Aug 28, 2012 at 05:24:40PM +0100, Peter Maydell wrote: > >> C99 7.1.3 > >> reserves underscore capital and double underscore prefixes. > > > > This is taking it out of context - reserved means different > > things in different parts of the spec. > > > > As far as I can see, 7.1.3 talks about what is permissible in headers: > > naturally when a libc implementation adds stuff in a header it would > > want to avoid breaking applications including this header. But > > it does not talk about what is permissible in a legal program - to avoid > > conflicts, you just need to use variables with reasonable names like > > kvmXXX qemuXXX or virtioXXX. > > 7.1.3 para 2 says "If the program declares or defines an identifier > in a context in which it is reserved [...] the behavior is undefined." > The rationale for 7.1.3 says that the underscore-cap and double > underscore identifiers are "reserved for the implementor" and that > "part of the name space of internal identifiers beginning with > underscore is available to the user" which implies that the rest > of that namespace is *not* available to the user. > > I think that's fairly clear that we can't use these identifiers > without entering the realm of undefined behavior. >
I'll have to re-read that, I missed it. What about _t in POSIX? That seems fairly safe if name is long and qemu specific enough. -- MST
