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<base href="https://bugs.documentfoundation.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_UNCONFIRMED "
title="UNCONFIRMED - Basic: Round VBA compatibility function implements wrong rounding mode"
href="https://bugs.documentfoundation.org/show_bug.cgi?id=142922">142922</a>
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<th>Summary</th>
<td>Basic: Round VBA compatibility function implements wrong rounding mode
</td>
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<th>Product</th>
<td>LibreOffice
</td>
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>All
</td>
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<th>OS</th>
<td>All
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<th>Status</th>
<td>UNCONFIRMED
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<th>Keywords</th>
<td>implementationError
</td>
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<th>Severity</th>
<td>normal
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<th>Priority</th>
<td>medium
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<th>Component</th>
<td>BASIC
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<th>Assignee</th>
<td>libreoffice-bugs@lists.freedesktop.org
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<th>Reporter</th>
<td>mikekaganski@hotmail.com
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<p>
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<pre>As explained in VBA documentation for Round [1]:
<span class="quote">> This VBA function returns something commonly referred to as bankers rounding.</span >
[MS-VBAL] [2] defined Banker's rounding as alternative name for
"round-to-even"; it is one of rounding modes defined in IEEE 754, its
recommended rounding mode for decimal [3].
[1] also provides some examples demonstrating the values returned bu VBA's
Round:
<span class="quote">> ?Round(0.12335,4)
> 0,1234
> ?Round(0.12345,4)
> 0,1234
> ?Round(0.12355,4)
> 0,1236
> ?Round(0.12365,4)
> 0,1236</span >
However, LibreOffice's Round function [4] implementation [5] does not implement
the required rounding mode. Executing the example calculations mentioned above
gives 0.1234, 0.1235, 0.1236, 0.1237.
FTR: we have a rtl_math_round function, that accepts a flag defining rounding
mode, rtl_math_RoundingMode_HalfEven among the possible values, which may be
used in the VBA function implementation.
[1]
<a href="https://docs.microsoft.com/en-us/office/vba/language/reference/user-interface-help/round-function">https://docs.microsoft.com/en-us/office/vba/language/reference/user-interface-help/round-function</a>
[2]
<a href="https://docs.microsoft.com/en-us/openspecs/microsoft_general_purpose_programming_languages/ms-vbal/98152b5a-4d86-4acb-b875-66cb1f49433e">https://docs.microsoft.com/en-us/openspecs/microsoft_general_purpose_programming_languages/ms-vbal/98152b5a-4d86-4acb-b875-66cb1f49433e</a>
[3] <a href="https://en.wikipedia.org/wiki/IEEE_754#Rounding_rules">https://en.wikipedia.org/wiki/IEEE_754#Rounding_rules</a>
[4]
<a href="https://help.libreoffice.org/7.2/en-US/text/sbasic/shared/03170000.html?DbPAR=BASIC">https://help.libreoffice.org/7.2/en-US/text/sbasic/shared/03170000.html?DbPAR=BASIC</a>
[5]
<a href="https://opengrok.libreoffice.org/xref/core/basic/source/runtime/methods1.cxx?r=86d298f8&mo=63707&fi=2377#2377">https://opengrok.libreoffice.org/xref/core/basic/source/runtime/methods1.cxx?r=86d298f8&mo=63707&fi=2377#2377</a>
[6]
<a href="https://opengrok.libreoffice.org/xref/core/sal/rtl/math.cxx?r=49af7e22&mo=38462&fi=1130#1130">https://opengrok.libreoffice.org/xref/core/sal/rtl/math.cxx?r=49af7e22&mo=38462&fi=1130#1130</a></pre>
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