Re: bug attached

[queency3 jones]

yes ! the local declaration solved my problem.
tnx very much .

On Thu, Aug 31, 2023 at 10:51 PM Andreas Kusalananda Kähäri <
andreas.kahari@abc.se> wrote:

> On Thu, Aug 31, 2023 at 10:38:55PM +0300, queency3 jones wrote:
> > i don't think that main is significant when it declared in "Bash" but
> even
> > though,
> > if you change the function main , to function ain  the $aa should be
> local
> > , but it ain't !!
>
> Function names being "main" or "ain" is irrelevant (the shell does
> not give significance to their name).  The scope of the variable "aa"
> is global in all functions in your example.  If you want a variable
> to be local to a function, you need to declare it as such.  Note that
> declaring a variable as local in your "main" function will give it a
> scope that stretches into the called "sub" function.  If you want the
> changes that "sub" makes to the variable be local to that function, then
> you need to declare it as local in "sub", like I showed.
>
> Quoting the manual:
>
>         Variables local to the function may be declared with the local
>         builtin command (local variables).  Ordinarily, variables and
>         their values are shared between the function and its caller.
>         If a variable is declared local, the variable's visible scope
>         is restricted to that function and its children (including the
>         functions it calls).
>
>
>
> >
> >
> > On Wed, Aug 30, 2023 at 5:59 PM Andreas Kusalananda Kähäri <
> > andreas.kahari@abc.se> wrote:
> >
> > > On Wed, Aug 30, 2023 at 03:40:21PM +0300, queency3 jones wrote:
> > > >
> > >
> > > > From: queency3@gmail.com
> > > > To: bug-bash@gnu.org
> > > > Subject: 2 same var name in different function causing mix
> > > >
> > > > Configuration Information [Automatically generated, do not change]:
> > > > Machine: x86_64
> > > > OS: linux-gnu
> > > > Compiler: gcc
> > > > Compilation CFLAGS: -g -O2
> > > -fdebug-prefix-map=/build/bash-2bxm7h/bash-5.0=.
> -fstack-protector-strong
> > > -Wformat -Werror=format-security -Wall -Wno-parentheses
> -Wno-format-security
> > > > uname output: Linux debian 4.19.0-25-amd64 #1 SMP Debian 4.19.289-2
> > > (2023-08-08) x86_64 GNU/Linux
> > > > Machine Type: x86_64-pc-linux-gnu
> > > >
> > > > Bash Version: 5.0
> > > > Patch Level: 3
> > > > Release Status: release
> > > >
> > > > Description:
> > > >
> > > > function sub { aa=8;return_value=$aa; }
> > > > function sub { aa=8; }
> > > >
> > > > function main { aa=3;sub;aa=$(($aa+1));printf "$aa\n"; }
> > > >
> > > >
> > > > calling main will print 9 instead of 4
> > > >
> > > >
> > >
> > > Not a bug.
> > >
> > > The code outputs "9" because the scope of the variable "aa" is global
> > > (once it has been created in "main").  The second function "sub" will
> > > therefore modify the value of the variable "aa" in the global scope.
> > > The change in the variabel's value will be visible in "main" after the
> > > call to "sub".
> > >
> > > To make the variable local to the "sub" function, use the "local"
> > > keyword:
> > >
> > >         function sub { local aa=8; }
> > >
> > > This will create a local variable "aa" in the function "sub" that will
> > > not be visible outside of the function.  In particular, it will not
> > > overwrite the global variable "aa" in "main" and the value of "aa" in
> > > "main" will remain unchanged (until you increment it from "3" to "4").
> > >
> > > On an unrelated note, you sohuld be printing the value using a static
> > > formatting string, like so:
> > >
> > >         printf '%s\n' "$aa"
> > >
> > > This avoids interpreting the value of the variable as a printf
> formatting
> > > string.
> > >
> > > --
> > > Andreas (Kusalananda) Kähäri
> > > SciLifeLab, NBIS, ICM
> > > Uppsala University, Sweden
> > >
> > > .
> > >
>
> --
> Andreas (Kusalananda) Kähäri
> SciLifeLab, NBIS, ICM
> Uppsala University, Sweden
>
> .
>