# Why ssl\_session\_cache\_api:size is strictly positive instead of non\_neg?

**URL:** <https://erlangforums.com/t/why-ssl-session-cache-api-size-is-strictly-positive-instead-of-non-neg/3728>\
**Category:** BEAM Chat / Discussions\
**Tags:** ssl\
**Created:** [June 17, 2024, 9:43am UTC](https://erlangforums.com/t/why-ssl-session-cache-api-size-is-strictly-positive-instead-of-non-neg/3728 "2024-06-17T09:43:09Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![maxlapshin](https://erlangforums.com/user_avatar/erlangforums.com/maxlapshin/32/1593_2.png) [@maxlapshin](https://erlangforums.com/u/maxlapshin)\
**Post date:** [June 17, 2024, 9:43am UTC](https://erlangforums.com/t/why-ssl-session-cache-api-size-is-strictly-positive-instead-of-non-neg/3728/1 "2024-06-17T09:43:09Z")

</div>

> <https://github.com/erlang/otp/blob/master/lib/ssl/src/ssl_session_cache_api.erl#L156>

```erlang
-callback size(CacheRef) -> Size when
      CacheRef:: session_cache_ref(),
      Size :: pos_integer().

```

Why zero is not allowed here?