diff options
Diffstat (limited to 'erts/emulator/test/num_bif_SUITE.erl')
| -rw-r--r-- | erts/emulator/test/num_bif_SUITE.erl | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/erts/emulator/test/num_bif_SUITE.erl b/erts/emulator/test/num_bif_SUITE.erl index 592542405f..290bb61fc8 100644 --- a/erts/emulator/test/num_bif_SUITE.erl +++ b/erts/emulator/test/num_bif_SUITE.erl @@ -213,6 +213,20 @@ fts_rand_float_decimals(N) -> [begin F0 = rand_float_reasonable(), L0 = float_to_list(F0, [{decimals, D}]), + case conform_with_io_lib_format_os(F0,D) of + false -> ok; + true -> + IOL = lists:flatten(io_lib:format("~.*f", [D, F0])), + true = case L0 =:= IOL of + true -> true; + false -> + io:format("F0 = ~w ~w\n", [F0, <<F0/float>>]), + io:format("decimals = ~w\n", [D]), + io:format("float_to_list = ~s\n", [L0]), + io:format("io_lib:format = ~s\n", [IOL]), + false + end + end, L1 = case D of 0 -> L0 ++ ".0"; _ -> L0 @@ -234,6 +248,26 @@ fts_rand_float_decimals(N) -> fts_rand_float_decimals(N-1). +conform_with_io_lib_format_os(F, D) -> + case os:type() of + {win32,_} -> + %% io_lib:format("~.*f") buggy on windows? OTP-15010 + false; + _ -> + conform_with_io_lib_format(F, D) + end. + +conform_with_io_lib_format(_, 0) -> + %% io_lib:format("~.*f") does not support zero decimals + false; +conform_with_io_lib_format(_, D) when D > 10 -> + %% Seems float_to_list gets it slightly wrong sometimes for many decimals + false; +conform_with_io_lib_format(F, D) -> + %% io_lib:format prints '0' for input bits beyond mantissa precision + %% float_to_list treats those unknown input bits as if they were zeros. + math:log2(abs(F) * math:pow(10,D)) < 54. + max_diff_decimals(F, D) -> IntBits = floor(math:log2(abs(F))) + 1, FracBits = (52 - IntBits), |