On Wed, Mar 21, 2018 at 05:39:48PM +0200, Michael S. Tsirkin wrote: > On Wed, Mar 21, 2018 at 03:19:22PM +0000, Daniel P. Berrangé wrote: > > On Wed, Mar 21, 2018 at 04:46:32PM +0200, Michael S. Tsirkin wrote: > > > Our current scheme is to use > > > #include "" > > > for internal headers, and > > > #include <> > > > for external ones. > > > > > > Unfortunately this is not based on compiler support: from C point of > > > view, the "" form merely looks up headers in the current directory > > > and then falls back on <> directories. > > > > > > Thus, for example, a system header trace.h - should it be present - will > > > conflict with our local trace.h > > > > If our local "trace.h" is in the current directory, then using "" > > is right and you can still use <trace.h> to get the system version. > > > > If our local trace.h is in include/ top level, then it is going to > > block use of the system trace.h regardless of whether we use <> or "" > > > > Fortunately our include/ tree uses sub-dirs, so we would typically > > use #include "$subdir/trace.h" and #include <trace.h> would still > > find the system header. > > We just have to be careful we don't add stuff at the top level of > > our include/ dir with names that are liable to clash. This might > > suggest renaming include/elf.h to include/qemu/elf.h, or just > > moving elf.h to the qemu/ subdirectory. Likewise include/glib-compat.h > > might be better moved to qemu/ subdirectory. > > > > This is exactly what this patch proposes, with a uniform scheme: > start everything with qemu/. > > > > > > As another example of problems, a header by the same name in the source > > > directory will always be picked up first - before any headers in > > > the include directory. > > > > There's only a couple of headers in the top level of our include/ > > directory - everything else is pulled in with a named path > > eg #include "block/block_int.h", so that would not conflict with > > reference to a bare #include "block_int.h" from the current directory. > > We can not know that there are no system headers that start with block/ on > any current or future systems.
Ah true, good point. I guess that's where the benefit of -iquote comes into play. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :| _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
