<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><br><div><div>The definition of pole error is stated in terms of the mathematical function, not the implementation of that function. The mathematical function either has a pole error or it doesn’t, regardless of how the function is implemented.</div><div><br></div><div>The definition of domain error is similar in this respect. Function specifications say "domain error occurs", not "domain error may occur”, in most cases, though not all.</div><div><br></div><div>The definition of range error doesn’t actually refer to the “mathematical function”: “a range error occurs if the mathematical result of the function cannot be represented in an object of the specified type, due to extreme magnitude”. However, I read this the same as if it said “the result of the mathematical function” instead of “the mathematical result of the function”. Implementations aren’t generally expected to precisely determine overflow thresholds (for the format). Hence, the function specifications are imprecise, for example, "A range error occurs if the magnitude of x is too large.”</div><div><br></div><div>So, it seems that when a function specification says an error occurs or an error may occur, it’s saying when the implementation shall or may report the error - even though the definitions of the kinds of errors are in terms of the mathematical function.</div><div><br></div><div>-Jim</div><div><br></div><div>On Apr 9, 2014, at 9:51 AM, Ian McIntosh <<a href="mailto:ianm@ca.ibm.com">ianm@ca.ibm.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div><p><font size="2" face="sans-serif">It may be hard to detect an exact infinite result when using a non-IEEE floating point implementation.</font><br>
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<font size="2" face="sans-serif">- Ian McIntosh IBM Canada Lab Compiler Back End Support and Development<br>
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<span><graycol.gif></span><font size="2" color="#424282" face="sans-serif">Jim Thomas ---2014-04-09 08:31:18 AM---Hmm. The definition says a pole error (also known as a singularity or infinitary) occurs if the mat</font><br>
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<ul style="padding-left: 4pt"><font size="1" color="#5F5F5F" face="sans-serif">From:</font></ul>
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<font size="1" face="sans-serif">Jim Thomas <<a href="mailto:jaswthomas@sbcglobal.net">jaswthomas@sbcglobal.net</a>></font></td></tr>
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<ul style="padding-left: 4pt"><font size="1" color="#5F5F5F" face="sans-serif">To:</font></ul>
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<font size="1" face="sans-serif">Rajan Bhakta <<a href="mailto:rbhakta@us.ibm.com">rbhakta@us.ibm.com</a>>, </font></td></tr>
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<ul style="padding-left: 4pt"><font size="1" color="#5F5F5F" face="sans-serif">Cc:</font></ul>
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<font size="1" face="sans-serif"><a href="mailto:cfp-interest@oakapple.net">cfp-interest@oakapple.net</a></font></td></tr>
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<ul style="padding-left: 4pt"><font size="1" color="#5F5F5F" face="sans-serif">Date:</font></ul>
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<font size="1" face="sans-serif">2014-04-09 08:31 AM</font></td></tr>
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<ul style="padding-left: 4pt"><font size="1" color="#5F5F5F" face="sans-serif">Subject:</font></ul>
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<font size="1" face="sans-serif">Re: [Cfp-interest] Pole errors action item result</font></td></tr>
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<ul style="padding-left: 4pt"><font size="1" color="#5F5F5F" face="sans-serif">Sent by:</font></ul>
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<font size="1" face="sans-serif"><a href="mailto:cfp-interest-bounces@oakapple.net">cfp-interest-bounces@oakapple.net</a></font></td></tr>
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<font size="3" face="serif">Hmm. The definition says</font><br>
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<font size="3" face="serif">a pole error (also known as a singularity or infinitary) occurs if the mathematical function has an exact infinite result as the finite input argument(s) are approached in the limit (for example, log(0.0)</font><br>
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<font size="3" face="serif">So pole errors occur. I guess what the committee means is the implementation is not required to report them.</font><br>
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<font size="3" face="serif">-Jim</font><br>
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<font size="3" face="serif">On Apr 9, 2014, at 2:29 AM, Rajan Bhakta <</font><a href="mailto:rbhakta@us.ibm.com"><font size="3" color="#0000FF" face="serif"><u>rbhakta@us.ibm.com</u></font></a><font size="3" face="serif">> wrote:</font><br>
<ul style="padding-left: 36pt"><font size="2" face="sans-serif">With regards to my action item regarding why "may" is used for pole errors:</font><font size="3" face="serif"> <br>
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Committee discussion: May is used since pole errors are not required to be present in C11.</font><font size="3" face="serif"> <br>
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Regards,<br>
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Rajan Bhakta<br>
z/OS XL C/C++ Compiler Technical Architect<br>
ISO C Standards Representative for Canada<br>
C Compiler Development<br>
Contact: </font><a href="mailto:rbhakta@us.ibm.com"><font size="2" color="#0000FF" face="sans-serif"><u>rbhakta@us.ibm.com</u></font></a><font size="2" face="sans-serif">, Rajan Bhakta/Houston/IBM</font><font size="3" face="serif">_______________________________________________<br>
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