Re: FreeTDS port to VMS V9.x on x86?

Liste des GroupesRevenir à co vms 
Sujet : Re: FreeTDS port to VMS V9.x on x86?
De : arne (at) *nospam* vajhoej.dk (Arne Vajhøj)
Groupes : comp.os.vms
Date : 01. Jul 2025, 21:14:19
Autres entêtes
Organisation : A noiseless patient Spider
Message-ID : <1041fir$2v6eo$2@dont-email.me>
References : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
User-Agent : Mozilla Thunderbird
On 6/26/2025 8:03 PM, Lawrence D'Oliveiro wrote:
On Tue, 24 Jun 2025 12:25:50 -0400, Arne Vajhøj wrote:
The algorithm is basically to try vsnprintf with buffers increasing in
size 512, 1024, 1536, ... until there is space.
>
That is very inefficient compared to just use the return value.
 It’s a good choice in the absence of any other clues as to how much to
allocate. I have used it myself. (Of course having an explicit number
returned is best of all.)
 One may conduct statistical analyses, I suppose to decide on the optimum
multiplication factor. E.g. would going up in powers of 3 better than
powers of 2? I suspect larger factors (too far from e = 2.71828 ...) would
not be worth using.
The specific factor is not as important as using multiplication instead
of addition.
Starting at 512 going towards a 1 GB CLOB:
+512 => 2 million
*1.5 => 36
*2 => 21
*3 => 13

And don’t forget to do a realloc(3) at the end, to trim the unused part of
the last allocation.
That seems very natural.
But for FreeTDS dbfcmd then it has:
vasprintf call to format buffer
test of return value
dbcmd call with buffer
free call for buffer
No point in realloc.
And I suspect that the pattern is common: format, use
once and free immediately.
So I don't know if it makes sense.
Arne

Date Sujet#  Auteur
3 Jun 25 * FreeTDS port to VMS V9.x on x86?56Richard Jordan
3 Jun 25 `* Re: FreeTDS port to VMS V9.x on x86?55Arne Vajhøj
3 Jun 25  `* Re: FreeTDS port to VMS V9.x on x86?54Arne Vajhøj
3 Jun 25   +* Re: FreeTDS port to VMS V9.x on x86?45Craig A. Berry
5 Jun 25   i`* Re: FreeTDS port to VMS V9.x on x86?44Arne Vajhøj
5 Jun 25   i `* Re: FreeTDS port to VMS V9.x on x86?43Arne Vajhøj
5 Jun 25   i  `* Re: FreeTDS port to VMS V9.x on x86?42Simon Clubley
5 Jun 25   i   `* Re: FreeTDS port to VMS V9.x on x86?41Craig A. Berry
6 Jun 25   i    `* Re: FreeTDS port to VMS V9.x on x86?40Arne Vajhøj
6 Jun 25   i     `* Re: FreeTDS port to VMS V9.x on x86?39Craig A. Berry
6 Jun 25   i      `* Re: FreeTDS port to VMS V9.x on x86?38Arne Vajhøj
6 Jun 25   i       `* Re: FreeTDS port to VMS V9.x on x86?37Craig A. Berry
6 Jun 25   i        `* Re: FreeTDS port to VMS V9.x on x86?36Arne Vajhøj
6 Jun 25   i         `* Re: FreeTDS port to VMS V9.x on x86?35Arne Vajhøj
23 Jun 25   i          `* Re: FreeTDS port to VMS V9.x on x86?34Craig A. Berry
24 Jun 25   i           `* Re: FreeTDS port to VMS V9.x on x86?33Arne Vajhøj
24 Jun 25   i            `* Re: FreeTDS port to VMS V9.x on x86?32Lawrence D'Oliveiro
24 Jun 25   i             `* Re: FreeTDS port to VMS V9.x on x86?31Arne Vajhøj
24 Jun 25   i              +* Re: FreeTDS port to VMS V9.x on x86?3Lawrence D'Oliveiro
24 Jun 25   i              i`* Re: FreeTDS port to VMS V9.x on x86?2Arne Vajhøj
24 Jun 25   i              i `- Re: FreeTDS port to VMS V9.x on x86?1Lawrence D'Oliveiro
24 Jun 25   i              `* Re: FreeTDS port to VMS V9.x on x86?27Craig A. Berry
24 Jun 25   i               `* Re: FreeTDS port to VMS V9.x on x86?26Arne Vajhøj
24 Jun 25   i                +- Re: FreeTDS port to VMS V9.x on x86?1Arne Vajhøj
24 Jun 25   i                `* Re: FreeTDS port to VMS V9.x on x86?24Arne Vajhøj
24 Jun 25   i                 `* Re: FreeTDS port to VMS V9.x on x86?23Craig A. Berry
24 Jun 25   i                  `* Re: FreeTDS port to VMS V9.x on x86?22Arne Vajhøj
25 Jun 25   i                   +* Re: FreeTDS port to VMS V9.x on x86?19Arne Vajhøj
25 Jun 25   i                   i`* Re: FreeTDS port to VMS V9.x on x86?18Craig A. Berry
1 Jul 25   i                   i `* Re: FreeTDS port to VMS V9.x on x86?17Arne Vajhøj
2 Jul 25   i                   i  +- Re: FreeTDS port to VMS V9.x on x86?1Lawrence D'Oliveiro
3 Jul 25   i                   i  `* Re: FreeTDS port to VMS V9.x on x86?15Arne Vajhøj
3 Jul 25   i                   i   `* Re: FreeTDS port to VMS V9.x on x86?14Dan Cross
3 Jul 25   i                   i    `* Re: FreeTDS port to VMS V9.x on x86?13Arne Vajhøj
3 Jul 25   i                   i     +* Re: FreeTDS port to VMS V9.x on x86?9Dan Cross
3 Jul 25   i                   i     i+* Re: FreeTDS port to VMS V9.x on x86?6Craig A. Berry
4 Jul 25   i                   i     ii+* Re: FreeTDS port to VMS V9.x on x86?4Arne Vajhøj
4 Jul 25   i                   i     iii`* Re: FreeTDS port to VMS V9.x on x86?3Craig A. Berry
4 Jul02:14   i                   i     iii `* Re: FreeTDS port to VMS V9.x on x86?2Arne Vajhøj
4 Jul05:38   i                   i     iii  `- Re: FreeTDS port to VMS V9.x on x86?1Dan Cross
4 Jul05:31   i                   i     ii`- Re: FreeTDS port to VMS V9.x on x86?1Dan Cross
4 Jul 25   i                   i     i`* Re: FreeTDS port to VMS V9.x on x86?2Arne Vajhøj
4 Jul06:06   i                   i     i `- Re: FreeTDS port to VMS V9.x on x86?1Dan Cross
4 Jul 25   i                   i     `* Re: FreeTDS port to VMS V9.x on x86?3Lawrence D'Oliveiro
4 Jul02:21   i                   i      `* Re: FreeTDS port to VMS V9.x on x86?2Arne Vajhøj
4 Jul02:41   i                   i       `- Re: FreeTDS port to VMS V9.x on x86?1Lawrence D'Oliveiro
27 Jun 25   i                   `* Re: FreeTDS port to VMS V9.x on x86?2Lawrence D'Oliveiro
1 Jul 25   i                    `- Re: FreeTDS port to VMS V9.x on x86?1Arne Vajhøj
3 Jun 25   +- Re: FreeTDS port to VMS V9.x on x86?1Richard Jordan
14 Jun 25   `* Re: FreeTDS port to VMS V9.x on x86?7Arne Vajhøj
15 Jun 25    `* Re: FreeTDS port to VMS V9.x on x86?6Lawrence D'Oliveiro
15 Jun 25     `* Re: FreeTDS port to VMS V9.x on x86?5Arne Vajhøj
15 Jun 25      `* Re: FreeTDS port to VMS V9.x on x86?4Lawrence D'Oliveiro
16 Jun 25       `* Re: FreeTDS port to VMS V9.x on x86?3Arne Vajhøj
16 Jun 25        `* Re: FreeTDS port to VMS V9.x on x86?2Lawrence D'Oliveiro
16 Jun 25         `- Re: FreeTDS port to VMS V9.x on x86?1Arne Vajhøj

Haut de la page

Les messages affichés proviennent d'usenet.

NewsPortal