It depends on the scope that the NEW_VAR is intended to work at (function
scope or namespace scope). At namespace scope you could do:
```c++
template <int>
auto _benchmarks = 0;
#define BENCHMARK(fn) \
auto _benchmarks<counter()> =
(::benchmark::internal::RegisterBenchmarkInternal(#fn, fn));

```

Something similar could probably be done in function scope, or by using
regular function calls instead.

On Tue, Aug 27, 2024, 04:17 Jeremy Rifkin via Std-Proposals <
std-proposals_at_[hidden]> wrote:

> The first approach I tried was what Thiago suggested. The second was:
>
> // t.cpp
> __COUNTER__
> #include "t.hpp"
>
> // t.hpp
> #if __COUNTER__ != 0
> #include __FILE__
> #endif
>
>
> Jeremy
>
> On Mon, Aug 26, 2024 at 5:22 PM Arthur O'Dwyer
> <arthur.j.odwyer_at_[hidden]> wrote:
> >
> > On Mon, Aug 26, 2024 at 3:16 PM Jeremy Rifkin via Std-Proposals <
> std-proposals_at_[hidden]> wrote:
> >>
> >> Good idea. I gave that a try as well as another approach but was
> >> unable to produce a sufficiently large __COUNTER__ before gcc
> >> segfaulted after (around a count of 270 million). I'm impartial on
> >> specifying a 32-bit counter vs a 64-bit counter, both seem reasonable
> >> to me.
> >
> >
> > Could you share your approach?
> > For comparison, I used this Python script to generate 50 million
> __COUNTER__ invocations:
> >
> > cat >test.py <<EOF
> > import sys
> > print("""
> > #define C __COUNTER__
> > #define D C|C|C|C|C|C|C|C|C|C
> > #define S static_assert(D|D|D|D|D|D|D|D|D|D)
> > #define T S;S;S;S;S;S;S;S;S;S
> > #define U T;T;T;T;T;T;T;T;T;T
> > """)
> > for i in range(int(sys.argv[1])):
> > print("U;")
> > print("")
> > EOF
> > time python test.py 5000 >test.cpp ; time clang++ test.cpp -fsyntax-only
> -std=c++17
> >
> > This compilation takes about 30 seconds on my machine.
> > But AppleClang starts ICEing ("translation unit is too large for Clang
> to process: ran out of source locations") somewhere between 50 million and
> 100 million, so that didn't tell me anything about the practical behavior
> of its __COUNTER__ on overflow.
> >
> > FWIW, looking at the actual code of each compiler, it's easy to tell
> that...
> > - Clang uses an `unsigned` 32-bit __COUNTER__, and wraps to zero on
> overflow.
> > - GCC uses an `unsigned int` 32-bit __COUNTER__, and wraps to zero on
> overflow.
> >
> > Cheers,
> > Arthur
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