How to write an "if exists, get, otherwise insert"

[2A5F]

How to write an "if exists, get, otherwise insert"

[greg7mdp]

Which hash_map are you using? And is it in a multi-thread context?

[2A5F]

parallel_flat_hash_map, yes, in a multi-thread context

[greg7mdp]

You can use lazy_emplace_l.