Path: csiph.com!eternal-september.org!feeder.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Keith Thompson Newsgroups: comp.lang.c Subject: Re: double free Date: Wed, 13 Jul 2016 16:19:57 -0700 Organization: None to speak of Lines: 65 Message-ID: References:

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<87a8hls155.fsf@bsb.me.uk> <874m7tryaj.fsf@bsb.me.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit Injection-Info: mx02.eternal-september.org; posting-host="945944de09706c9b4e29b53c9d2efdc2"; logging-data="25236"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+EOrXhmEbGsoErdnMjEz5f" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1 (gnu/linux) Cancel-Lock: sha1:otRhDEXJGyb0JaeXGtXaxcv4CCA= sha1:6sOf+ACYZHNN8314oLE/iYKi3yM= Xref: csiph.com comp.lang.c:90359 "Osmium" writes: > "Ben Bacarisse" wrote in message > news:874m7tryaj.fsf@bsb.me.uk... >> Keith Thompson writes: >> >>> Ben Bacarisse writes: >>>> Richard Heathfield writes: >>>>> On 13/07/16 21:02, Keith Thompson wrote: >>>> >>>>>> There are a number of languages that use ** as the >>>>>> exponentiation operator (Ada, Perl, Python, Ruby). And when I use >>>>>> those languages, the fact that ** means exponentation has never been >>>>>> a problem for me. >>>>> >>>>> Nor me. But it could just as well be &$& or )( or *! or @~ or _power_ >>>>> or just about anything else. So why **? >>>> >>>> I suspect it's mnemonic for "repeated multiplication". Why × never made >>>> it into early computer character repertoires (making * a reasonable >>>> second best) is a deeper mystery. >>>> >>>> >>> >>> × is not in ASCII or EBCDIC, though that's probably an effect rather >>> than a cause. >>> >>> A Google search turned up this quote attributed to Guy Steele: >>> >>> Fortran was invented on accounting equipment. They were using >>> keypunches that had character sets designed for business use. There >>> was no multiplication symbol on a keypunch, so they settled on the >>> asterisk as a compromise. >> >> Hmm... Early FORTRAN documentation (circa 1955) uses Ă— for >> multiplication and Ă—Ă— for exponentiation. > > That's odd. I'm quite sure that there no computers in the USA that could > print that symbol. Confirmed. This document: http://archive.computerhistory.org/resources/text/Fortran/102679231.05.01.acc.pdf dated 1954, and titled as a "preliminary report", uses `Ă—` and `Ă—Ă—` for multiplication and exponentiation. The `Ă—` characters appear to be hand-written. Speculation: The font used for the document didn't have a multiplication symbol, so the multiplication symbols were hand-written because the letter `x` has serifs. Since it's a preliminary report, the authors might not yet have realized that the multiplication symbol would be unavailable on the target system (IBM 704). http://archive.computerhistory.org/resources/text/Fortran/102649787.05.01.acc.pdf (dated 1956) uses "*" and "**". Interestingly, the source code examples in the 1954 manual are mostly in lower case; the 1956 manual uses all-caps. (I don't know whether the multiplication symbols are going to be sent correctly.) -- Keith Thompson (The_Other_Keith) kst-u@mib.org Working, but not speaking, for JetHead Development, Inc. "We must do something. This is something. Therefore, we must do this." -- Antony Jay and Jonathan Lynn, "Yes Minister"