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POWhat _did_ the C operators /\ and \/ do?
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copied!<p>Anyone can "declare" ones own operators in C.... that is if one is a C compiler guru and has the source code to the C compiler! ;-)</p> <p>Further questions to puzzle:</p> <ol start="5"> <li>How are these operations done in C99? gcc? ...</li> <li>And why were /\ & \/ dropped?</li> <li>Which types were the /\ and \/ operators valid for?</li> </ol> <p>Googling for "/\ \/" naturally returns nothing. Wikipedia has a page for neither /\ nor \/. But I have spotted form similar operators are built into the XML character entities! <HR><i>Source added:</i> I found the offending example in the PDP's cc source file "c00.c":</p> <pre><code>/* * Return the next symbol from the input. * peeksym is a pushed-back symbol, peekc is a pushed-back * character (after peeksym). * mosflg means that the next symbol, if an identifier, * is a member of structure or a structure tag or an enum tag */ symbol() { ... case BSLASH: if (subseq('/', 0, 1)) return(MAX); goto unkn; case DIVIDE: if (subseq('\\', 0, 1)) return(MIN); if (subseq('*',1,0)) return(DIVIDE); ... } </code></pre> <p><hr> <i>Actual Implementations:</i> The /\ and \/ operators date back as far as <a href="http://en.wikipedia.org/wiki/Sixth_Edition_Unix" rel="nofollow noreferrer">Sixth Edition Unix</a> 1975 (so far). Examples: <a href="http://www.bitsavers.org/bits/Interdata/32bit/unix/univWollongong_v6/interdata_v6/usr/source/c/c00.c" rel="nofollow noreferrer">Unix V6</a>(1975), <a href="http://stuff.mit.edu/afs/sipb/project/v7unix/fs/usr/src/cmd/c/c00.c" rel="nofollow noreferrer">Unix V7</a>(1979) and more currently <a href="http://ftp.gcu.info/tuhs/PDP-11/Trees/2.11BSD/usr/src/lib/ccom/c00.c" rel="nofollow noreferrer">BSD 2.11</a>(1992-<a href="http://en.wikipedia.org/wiki/Berkeley_Software_Distribution#cite_note-2.11bsd-0" rel="nofollow noreferrer">2008</a>)</p>

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