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- From: cameron@symcom.math.uiuc.edu (Cameron Smith)
- Subject: Re: Big TeX's -- how hard are they to come by?
- References: <BuEC6r.B47@news.cso.uiuc.edu> <18p7lpINNc73@almaak.usc.edu>
- Message-ID: <BuEEFr.Bz9@news.cso.uiuc.edu>
- Sender: usenet@news.cso.uiuc.edu (Net Noise owner)
- Organization: none
- Date: Fri, 11 Sep 1992 05:11:49 GMT
- Lines: 30
-
- In article <18p7lpINNc73@almaak.usc.edu> ajayshah@almaak.usc.edu
- (Ajay Shah) writes:
- >cameron@symcom.math.uiuc.edu (Cameron Smith) [That's me!] writes:
- >>Are there enough free Big TeX implementation available nowadays that
- >>I can simply tell someone who's running out of memory to go get one?
- >
- >I find it hard to appreciate why TeX should not know how to dynamically
- >allocate RAM on demand. Does this have something to do with being
- >written in pascal? I seem to recall that new() returns nil if
- >you are out of memory.
-
- I don't have the source code to TeX (Volume B of Computers & Typesetting)
- available just now (I returned it to the library; couldn't justify buying
- a copy), and I didn't study it closely when I did have it, but I seem
- to recall DEK's having made a comment that he wasn't happy about
- having to statically pre-allocate tables to hold all of TeX's
- data structures, but that since Pascal implementations were so
- non-standard in their handling of new() he had no choice. In particular
- I believe he specifically stated that on some Pascals a call to new()
- when there wasn't enough memory available would either crash the program
- or return a pointer to random garbage. Of course the Pascal you use
- today may do something more sensible, but (a) this was about 15 years
- ago, and (b) he was writing for the lowest common denominator, trying
- to allow for worst-case behavior. (And a darn good thing too; that's
- probably the reason that it has been possible to port TeX to so many
- systems having so little in common with one another.)
-
- >Ajay Shah, (213)749-8133, ajayshah@usc.edu
-
- Cameron Smith (cameron@symcom.math.uiuc.edu)
-