Use -1 "precision" in gen_stub.php #8734
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| * @cname M_E | ||
| */ | ||
| const M_E = 2.7182818284590452354; | ||
| const M_E = 2.718281828459045; |
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why is M_E declared here and no other math constants?
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Oh, indeed, that looks fishy. We use the definitions provided by libc, if available, and only define the macros ourselves otherwise. There is nothing special about M_E compared to the other constants (like M_PI).
However, given that we already go to great lengths to have portable floating point arithmetic, it may not be the best idea to rely on definitions provided by libc.
| { | ||
| REGISTER_DOUBLE_CONSTANT("M_E", M_E, CONST_CS | CONST_PERSISTENT); | ||
| ZEND_ASSERT(M_E == 2.7182818284590451); | ||
| ZEND_ASSERT(M_E == 2.718281828459045); |
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needed as compared as string here, https://3v4l.org/9C9LV
| Math constants | ||
| --INI-- | ||
| precision=14 | ||
| precision=-1 |
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we want to assert the full precision, double is used for both x86/x64 build
| --TEST-- | ||
| Test for pre-defined math constants | ||
| --INI-- | ||
| precision=14 |
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var_dump uses (correctly) always the full/-1 precision
| M_SQRT1_2 : 0.707106[0-9]* | ||
| M_SQRT3 : 1.732050[0-9]* | ||
| --EXPECT-- | ||
| M_E : 2.718281828459045 |
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on all platforms, the output should be strictly the same
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@bwoebi, @kocsismate, what do you think about this PR? |
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@bwoebi @kocsismate @cmb69 this PR sits here for a long time but is finished, can you please review? |
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This looks reasonable, but needs a rebase. |
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rebased |
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Thank you! |
3 participants
https://3v4l.org/FkrAj - only
-1results in the shortest 64-bit IEEE 754 floating-point representation possible,17can print more unneeded digitsalso improve two math constants tests by asserting the exact values