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<p class="MsoNormal">Hello,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">In today’s WG14 meeting the ++(E) quantum exponent issue came up again (that we discussion the March meeting this year).<o:p></o:p></p>
<p class="MsoNormal">Given later changes to the C standard wording (for _BitInt I believe) and what was already there for postfix, we will need to revisit this.<o:p></o:p></p>
<p class="MsoNormal">Joseph has a suggestion in a chat he sent me, but that of course is not necessarily the only way to resolve this issue.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Here are the comments I got:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">For ++E DFP quantum exponent issue:<o:p></o:p></p>
<p class="MsoNormal">From Joseph:<o:p></o:p></p>
<p class="MsoNormal">The issue is that the wording now consistently no longer says 1 in program font, it says 1 in appropriate type.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Based on the comment I made:<o:p></o:p></p>
<p class="MsoNormal">For the +1 quantum exponent issue, CFP discussed this before (in the March 2022 meeting) and this was our discussion (and conclusion):<o:p></o:p></p>
<p class="MsoNormal"> C/C++ defines ++ as adding the value 1 to the operand. For DFP, what is the quantum exponent of that 1?<o:p></o:p></p>
<p class="MsoNormal"> Zero is the quantum exponent. This follows from ++E is equivalent to (E)+=1 where the 1 is in program font meaning an int constant. The C conversion from int to decimal gives a preferred quantum exponent of zero. So the rules cover
this case already.<o:p></o:p></p>
<p class="MsoNormal"> No other result seems to make sense anyways.<o:p></o:p></p>
<p class="MsoNormal"> Perhaps say it is adding the integer one instead of using the font in the C text for that ++E to clarify?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"> Joseph: Postfix ++ and -- said "appropriate type" all along. Prefix changed for _BitInt, because 1 of type int is inappropriate for _BitInt. 1 of appropriate type i fine for both prefix and postfix *if* an additional explicit statement
of quantum exponent is added for the DFP case. (And it should be fine for that to be quantum exponent 0, as if integer 1 were used.)<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Regards,<br>
<br>
<b>Rajan Bhakta</b><br>
z/OS XL C/C++ Compiler Technical Architect<br>
ISO C Standards Representative (Canada, USA), PL22.11 Chair<br>
C/C++ Compiler Development<o:p></o:p></p>
<p class="MsoNormal">rbhakta@us.ibm.com<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">IBM<o:p></o:p></p>
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