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.

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!

{deps, [{otp_vsn, "~>1.0"}]}.

...
-include_lib("otp_vsn/include/otp_vsn.hrl").
...
-ifdef(OTP_VSN_HAS_MAPS).
-ifndef(OTP_VSN_19_AND_ABOVE).
... something using maps and specific to OTP 17 or 18 but not 19 nor above ...
-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)
  • Note on release candidates: 21.0-rc1 is expressed as "21.0.0", same for 21.0-rc2
• ?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)
• ?OTP_VSN_STACKTRACE, ?OTP_VSN_HAS_ST_MATCHING, ?OTP_VSN_IF_HAS_ST_MATCHING: see stacktrace matching macros

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

On ST matching

Since OTP 21 calls to erlang:get_stacktrace/0 (ST) generate a compilation warning and try...end blocks have a new syntax to extract the same information:

try ...
catch E:T:ST -> ...
end

In order to compile without these warnings and be backwards compatible we introduce a couple macros:

• ?OTP_VSN_STACKTRACE(T,E,ST): defined for all releases. The least annoying workaround by far IMO.
• ?OTP_VSN_IF_HAS_ST_MATCHING(Y), ?OTP_VSN_IF_HAS_ST_MATCHING(Y,N): see below and test/has_st_matching_tests.erl
• ?OTP_VSN_HAS_ST_MATCHING: defined for releases which have that syntax (i.e. all since OTP 21.0)

    catch
     %% Probably the one macro you're interested in:
        ?OTP_VSN_STACKTRACE(error, _, ST)
            begin f(ST), X end;
     %%  Its equivalent:
     %% ?OTP_VSN_IF_HAS_ST_MATCHING(
     %%    error:_:ST -> begin f(ST), X end;
     %%   ,error:_ -> begin f(erlang:get_stacktrace()), X end;
     %%   )
        ?OTP_VSN_IF_HAS_ST_MATCHING(throw:only_matching:ST -> f(X,ST);)
        ?OTP_VSN_IF_HAS_ST_MATCHING(throw:b:ST -> f(X,ST);, throw:b -> f(X,erlang:get_stacktrace());)
        ?OTP_VSN_IF_HAS_ST_MATCHING(_:_:ST -> f(X, ST),
                                    _:_    -> f(X, erlang:get_stacktrace()))
    end