README.md
# [otp_vsn](https://github.com/fenollp/otp_vsn) [](https://circleci.com/gh/fenollp/otp_vsn/tree/master) [](https://travis-ci.org/fenollp/otp_vsn)
Macros defined per Erlang/OTP version so you don't have to.
This saves you the copy/pasting/tweaking of [`erl_opts`'s `platform_define`](https://www.rebar3.org/docs/configuration#section-compilation).
Header-only, no dependencies. Supports releases from `R16B01` to latest.
Note: no need to include `otp_vsn` in your apps or releases. This should only be a compile-time dependency!
```erlang
{deps, [{otp_vsn, "~>1.0"}]}.
```
```erlang
...
-include_lib("otp_vsn/include/otp_vsn.hrl").
...
-ifdef(OTP_VSN_HAS_MAPS).
-ifndef(OTP_VSN_19_AND_ABOVE).
... something using maps and OTP 19-specific ...
-endif.
-endif.
...
```
## Macros
Note: all macros introduced by `otp_vsn` are prefixed with `OTP_VSN` and in full caps.
* **`?OTP_VSN`**: OTP version string in `MAJOR.MINOR.PATCH` format
* Zeros are added where needed (e.g. `"16.1.0"` for R16B01)
* `?OTP_VSN_MAJOR`: above `MAJOR` part as an integer
* `?OTP_VSN_MINOR`: above `MINOR` part as an integer
* `?OTP_VSN_PATCH`: above `PATCH` part as an integer
* `?OTP_VSN_MAJOR_STRING`: `?OTP_VSN_MAJOR` as a string
* `?OTP_VSN_MINOR_STRING`: `?OTP_VSN_MINOR` as a string
* `?OTP_VSN_PATCH_STRING`: `?OTP_VSN_PATCH` as a string
* **`?OTP_VSN_{{MAJOR}}_AND_ABOVE`**: defined & set to `true` for `?OTP_VSN = "?{{MAJOR}}.0.0"` and all later versions
* e.g. for OTP 19.0 `?OTP_VSN_19_AND_ABOVE = true`
* but on OTP 18.3 it is not defined
* but on OTP 20.3 it is defined as well as `OTP_VSN_20_AND_ABOVE`
* **`?OTP_VSN_HAS_MAPS`**: defined for releases which have maps (i.e. all since OTP 17.0)
If you'd like to see more macros you are welcome to
* open an issue at https://github.com/fenollp/otp_vsn/issues
* open a pull request at https://github.com/fenollp/otp_vsn/pulls
