From: usotsuki@buric.co (Steve Nickolas)
Subject: [TUHS] C declarations.
Date: Sun, 14 May 2017 10:58:18 -0400 (EDT) [thread overview]
Message-ID: <alpine.BSF.2.02.1705141057160.64059@frieza.hoshinet.org> (raw)
In-Reply-To: <201705141411.v4EEBYjv021607@coolidge.cs.Dartmouth.EDU>
On Sun, 14 May 2017, Doug McIlroy wrote:
>> Are there languages that copy arrays in function calls defaultly?
>
>> Pascal is an example.
>
> Pascal's var convention, where the distinction between value
> and reference is made once and for all for each argument of
> each function, is sound. The flexibility of PL/I, where the
> distinction is made at every call (parenthesize the name to
> pass an array by value) is finicky, though utterly general.
QuickBasic uses the ( ) trick too.
>> Where is all that [memory] going to come from if you pass a
>> large array on a memory-constrained system of specs common back in the
>> days when C was designed
>
> Amusingly, under the customary linkage method in the even earlier
> days when Fortran was designed, pass-by-reference entailed a big
> overhead that could easily dominate pass-by-value for small arrays.
>
> [In the beginning, when CPUs had only one register, subroutine
> preambles plugged the reference into every mention of that variable
> throughout the body of the subroutine. This convention persisted
> in Fortran, which was designed for a machine with three index
> registered. Since reference variables were sometimes necessary
> (think of swap(a,b) for example) they were made standard.]
>
> Doug
>
Three! O_O That's a lot, if you're used to the 6502 and its mere *two*
index registers.
-uso.
next prev parent reply other threads:[~2017-05-14 14:58 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-14 14:11 Doug McIlroy
2017-05-14 14:58 ` Steve Nickolas [this message]
-- strict thread matches above, loose matches on Subject: below --
2017-05-15 18:47 Steve Johnson
2017-05-15 19:54 ` Bakul Shah
2017-05-16 7:25 ` George Ross
2017-05-13 23:11 Richard Tobin
2017-05-15 6:46 ` Tim Bradshaw
2017-05-12 14:04 Richard Tobin
2017-05-11 21:49 Ron Natalie
2017-05-11 22:01 ` Arthur Krewat
2017-05-11 23:44 ` Dave Horsfall
2017-05-11 22:03 ` David Arnold
2017-05-11 22:32 ` Larry McVoy
2017-05-11 22:41 ` Ron Natalie
2017-05-13 1:24 ` Larry McVoy
2017-05-13 2:45 ` Ron Natalie
2017-05-13 12:20 ` Michael Kjörling
2017-05-13 12:35 ` Tim Bradshaw
2017-05-13 12:42 ` Michael Kjörling
2017-05-13 15:36 ` Stephen Kitt
2017-05-14 1:59 ` Lawrence Stewart
2017-05-14 2:23 ` Dave Horsfall
2017-05-14 4:24 ` Bakul Shah
2017-05-14 6:12 ` Steve Johnson
2017-05-14 6:48 ` Bakul Shah
2017-05-14 23:06 ` Ron Natalie
2017-05-14 23:34 ` Arthur Krewat
2017-05-15 0:14 ` Dan Cross
2017-05-15 0:23 ` Ron Natalie
2017-05-15 3:43 ` Random832
2017-05-15 0:40 ` Larry McVoy
2017-05-15 2:00 ` Nevin Liber
2017-05-15 10:21 ` Tony Finch
2017-05-15 4:35 ` Dave Horsfall
2017-05-15 4:54 ` Bakul Shah
2017-05-15 5:01 ` Dave Horsfall
2017-05-15 12:58 ` Michael Kjörling
2017-05-15 16:58 ` Dave Horsfall
2017-05-13 13:46 ` Hellwig Geisse
2017-05-13 19:08 ` Random832
2017-05-13 23:21 ` Dave Horsfall
2017-05-14 14:48 ` Nemo
2017-05-13 19:05 ` Random832
2017-05-14 13:14 ` Derek Fawcus
2017-05-12 0:15 ` Bakul Shah
2017-05-12 2:41 ` Theo Pavlidis
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