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Re: Incrementing variable=0 with arithmetic expansion causes Return code = 1

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On 28/08/2020 09:00 am, Gabriel Winkler wrote:
> Configuration Information [Automatically generated, do not change]:
> Machine: x86_64
> OS: linux-gnu
> Compiler: gcc -I/home/abuild/rpmbuild/BUILD/bash-4.4 -L/home/abuild/rpmbuild/BUILD/bash-4.4/../readline-7.0
> Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='x86_64' -DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='x86_64-suse-linux-gnu' -DCONF_VENDOR='suse' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' -DSHELL -DHAVE_CONFIG_H   -I.  -I. -I./include -I./lib   -fmessage-length=0 -grecord-gcc-switches -O2 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector-strong -funwind-tables -fasynchronous-unwind-tables -fstack-clash-protection -g  -D_GNU_SOURCE -DRECYCLES_PIDS -Wall -g -Wuninitialized -Wextra -Wno-switch-enum -Wno-unused-variable -Wno-unused-parameter -Wno-parentheses -ftree-loop-linear -pipe -DBNC382214=0 -DIMPORT_FUNCTIONS_DEF=0 -fprofile-use -fprofile-correction
> uname output: Linux sophie 4.12.14-150.32-default #1 SMP Thu Aug 1 08:42:52 UTC 2019 (a2a3983) x86_64 x86_64 x86_64 GNU/Linux
> Machine Type: x86_64-suse-linux-gnu
> 
> Bash Version: 4.4
> Patch Level: 23
> Release Status: release
> 
> Description:
> If I have a variable with the value 0 assigned to it incrementing it causes the return code to be 1, even though the variable has been incremented successfully. This only happens if the value of the variable is 0. With positive and negative values this bug is no present.
> 
> Repeat-By:
> # Works fine
> test=1
> ((test++))
> echo $?
> 0
> echo $test
> 2
> 
> # Causes error
> test=0
> ((test++))
> echo $?
> 1
> echo $test
> 1
> 
> 
> ​Best Regards
> 
> Gabriel Winkler
> 
> _________________________
> 
> bpm consult ag
> beeline solutions
> Gabriel Winkler
> DevOps Engineer
> Industriestrasse Ost 10
> CH-4614 Hägendorf
> 
> Telefon +41 61 417 10 68
> Web     www.bpm.ch<http://www.bpm.ch/>
> 

 From man bash:

((expression))
The expression is evaluated according to the rules described
below under ARITHMETIC EVALUATION.  If the value of the
expression is non-zero, the return status is 0; otherwise the
return status is 1.  This is exactly equivalent to
let "expression".



-- 
Chris Elvidge
England

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Re: Incrementing variable=0 with arithmetic expansion causes Return code = 1 Chris Elvidge <celvidge001@gmail.com> - 2020-08-28 14:42 +0100

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