segmentation violation in debug mode when watching for an index of an array and rerunning

[Pascal Maugis]

In debug mode, watching for operation on the index of an array is 
possible (et very usefull). However, when rerunning the program while 
the watch is still active leads to segmentation violation :

   zsh> echo "a[1]=2" >! a.awk
   zsh> gawk -D -f ./a.awk
   *gawk> b *1
        Point d'arret 1 defini dans le fichier « ./a.awk » ligne 1
   *gawk> r*
        Demarrage du programme :
        Arrêt dans Rule...
        Breakpoint 1, main() à « ./a.awk »:1
        1       a[1]
   gawk> n
   gawk> w a[1]
   Watchpoint 2: a["1"]
   gawk> r
        Programme en cours. Reprendre depuis le debut (o/n) ? o
   *    gawk: fatal : erreur interne : erreur de segmentation*
        [2]    1001153 abort (core dumped)  gawk -D -f ./a.awk

Obviously, after rerun, 'watch' points to an adress which is not 
allocated anymore (which is logic). I guess watchpoints on array indexes 
should be disabled on rerun, or reenabled only when the array is defined 
again as such. Watching a whole array ('watch a') works fine.

Cheers,

Pascal.

Le 13/09/2022 à 12:42, Pascal Maugis a écrit :
> Hi, as promised here is the strange, unexpected behavior of ++ that 
> looks like an error to me, because in "a ++b", a is incremented 
> instead of b. "a b++" and "a++ b" produce the correct results however :
>
>     touch a.awk
>     gawk -D -f ./a.awk
>     eval "a=1 ; b=2"
>     eval "print a ++b"   ; output = 12 : (variables will be
>     incremented after the operation, ok with me as documented)
>     eval "print a b"     ; output = 22 : a has been incremented
>     instead of b
>     eval "print a++b"    ; output = 22 :
>     eval "print a b"     ; output = 32 : a has been incremented
>
> The operation seems to be interpreted as "a++b", the space been 
> uninterpreted as a separator
>
> Thanks for your insight,
>
> Cheers,
>
> Pascal.
>
> --
> ------------------------------------------------------------------------
>
> *Pascal MAUGIS*
> Modélisation hydrologique et changement climatique, PhD
>
> LSCE
>
> Laboratoire des Sciences du Climat et de l'Environnement 
> <http://www.lsce.ipsl.fr/>
>
> Unité Mixte de Recherche CEA-CNRS-UVSQ (UMR 8212), IPSL, Paris-Saclay
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>
> e-mail : pascal.maugis@lsce.ipsl.fr
> Page perso : FR <http://www.lsce.ipsl.fr/Pisp/pascal.maugis/> - EN 
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> Tel./Fax : +33 1 69 08 75 24 / +33 1 69 08 77 16
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--
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*Pascal MAUGIS*
Modélisation hydrologique et changement climatique, PhD

LSCE

Laboratoire des Sciences du Climat et de l'Environnement 
<http://www.lsce.ipsl.fr/>

Unité Mixte de Recherche CEA-CNRS-UVSQ (UMR 8212), IPSL, Paris-Saclay
Equipe MOSAIC : MOdelisation des SurfAces et Interfaces Continentales
Bât. 714, pièce 2115
C.E. Saclay, Orme des Merisiers, 91191 Gif-sur-Yvette Cedex, FRANCE

e-mail : pascal.maugis@lsce.ipsl.fr
Page perso : FR <http://www.lsce.ipsl.fr/Pisp/pascal.maugis/> - EN 
<http://www.lsce.ipsl.fr/en/Phocea/Pisp/index.php?nom=pascal.maugis>
Tel./Fax : +33 1 69 08 75 24 / +33 1 69 08 77 16

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