On Tue, 11 Aug 2020 at 14:56, Nathan Sidwell <nat...@acm.org> wrote: > > On 8/7/20 10:06 AM, Luis Machado via Gcc wrote: > > Hi, > > > > cc-ing the GCC mailing list, as we may want to use the same coding style > > for GDB and GCC. > > > > Yesterday I brought this topic up on IRC. I notice we started using more > > and more the "auto" keyword. In some cases, this is actually useful and > > makes the code a bit more compact. GDB has been using those more often, > > whereas GCC, for example, isn't using those too much. > > > > Looking at the coding standards for GCC > > (https://gcc.gnu.org/codingconventions.html), I don't see anything > > dictating best practices for "auto" use. > > > > I guess it is a consensus that "auto" is a good fit when dealing with > > iterators, lambda's and gnarly templates (but only when the type is > > already obvious from its use). > > > > There are other situations where "auto" may make things a little more > > cryptic when one wants to figure out the types of the variables. One > > example of this is when you have a longer function, and you use "auto" > > in a variable that lives throughout the scope of the function. This > > means you'll need to go back to its declaration and try to figure out > > what type this particular variable has. > > > > Pedro has pointed out LLVM's coding standards for "auto", which we may > > or may not want to follow/adopt: > > https://llvm.org/docs/CodingStandards.html#use-auto-type-deduction-to-make-code-more-readable > > > > > > It sounds like a reasonable idea to me. Thoughts? > > I agree, it's the way I use auto. I particularly like the > auto *foo = expr; > idiom, when you're getting a pointer, but the type of the pointee is > clear. It informs how you use 'foo'.
Yes, great suggestion. I use that in libstdc++ too, e.g. include/bits/shared_ptr.h: if (auto* __p = dynamic_cast<typename _Sp::element_type*>(__r.get()))
