How to avoid warning when using scope guard?

Question

I am using folly scope guard, it is working, but it generates a warning saying that the variable is unused:

warning: unused variable ‘g’ [-Wunused-variable]

The code:

folly::ScopeGuard g = folly::makeGuard([&] {close(sock);});

How to avoid such warning?

Answer 1

You can just label the variable as being unused:

folly::ScopeGuard g [[gnu::unused]] = folly::makeGuard([&] {close(sock);});

Or cast it to void:

folly::ScopeGuard g = folly::makeGuard([&] {close(sock);});
(void)g;

Neither is great, imo, but at least this lets you keep the warnings.