On Wed, Feb 22, 2023 at 08:17:09AM +0000, Richard W.M. Jones wrote: > > > We may still want some division of: > > > > > > DEFINE_VECTOR_TYPE (int_vector, int); > > > DEFINE_POINTER_VECTOR_TYPE (string_vector, char *, free); > > > > > > where under the hood, DEFINE_POINTER_VECTOR_TYPE(type, base, fn) > > > invokes both DEFINE_VECTOR_TYPE(type, base) and > > > DEFINE_VECTOR_EMPTY(type, fn), or whatever we name the second > > > function. > > I quite like Eric's suggestion, but it's probably too much complexity > for this patch series. > > > This is doable, but I hope it's not expected that > > DEFINE_POINTER_VECTOR_TYPE() *enforce* that the element type be a pointer :) > > > You might ignore this for a first draft, but it is apparently possible > to statically detect this (at least, if using GCC/clang): > > https://stackoverflow.com/questions/19255148/check-if-a-macro-argument-is-a-pointer-or-not >
That particular question worries about a macro that compiles without error for both pointer and scalar types as arguments; a simpler macro compiles correctly for pointers (and perhaps an array that decays to a pointer, if we want that), while causing compilation error on a scalar, reinforcing that it is an error to use the macro on a non-pointer. But ideas about the future don't need to hold up the present. > > > ADD_VECTOR_EMPTY_METHOD() instead of DEFINE_VECTOR_EMPTY() works for > > > me. > > > > OK, ADD_VECTOR_EMPTY_METHOD() can work with the above. > > This sounds fine for now, and since these are implementation details > we can always revisit them in future. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org _______________________________________________ Libguestfs mailing list Libguestfs@redhat.com https://listman.redhat.com/mailman/listinfo/libguestfs
