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oBdA write it already: there is no function in a command shell batch. You can only call/jump to methods. But you can set global variables. <br />
<br />
In the case of different batch files: The process is called piping. Thus the use of Echo to output the result to the standard pipe is the correct approach.<br />
<br />
So I would thus use a slightly different syntax for the &quot;function&quot; result in a closed batch, call it a different flavor:<br />
<br />

<pre><code id="code-20-42686504-1">@Echo Off
SetLocal

Set Str1=1,2,3,4,5
Set Str2=6,7,8,9
Call :JoinStrings &quot;%Str1%&quot; &quot;%Str2%&quot;
Echo Result: %_Result%

EndLocal
GoTo :Eof

:JoinStrings  &lt;String 1&gt; &lt;String 2&gt;
SetLocal

Set Str1=%~1
Set str2=%~2
Set Result=%Str1%,%Str2%

EndLocal &amp; Set _Result=%Result%
GoTo :Eof</code></pre>
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oBdA write it already: there is no function in a command shell batch. You can only call/jump to methods. But you can set global variables.

In the case of different batch files: The process is called piping. Thus the use of Echo to output the result to the standard pipe is the correct approach.

So I would thus use a slightly different syntax for the "function" result in a closed batch, call it a different flavor:



@Echo Off
SetLocal

Set Str1=1,2,3,4,5
Set Str2=6,7,8,9
Call :JoinStrings "%Str1%" "%Str2%"
Echo Result: %_Result%

EndLocal
GoTo :Eof

:JoinStrings  <String 1> <String 2>
SetLocal

Set Str1=%~1
Set str2=%~2
Set Result=%Str1%,%Str2%

EndLocal & Set _Result=%Result%
GoTo :Eof

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I have two batch files A.bat and B.bat. A.bat is calling to B.bat.<br />
B.bat is doing some processing, and return back the result to A.bat. How A.bat can accept the return?<br />
<br />
A.bat <br />
@echo off<br />
set str1=1,2,3,4,5<br />
set str2=6,7,8,9<br />
call B.bat %str1% %str2%<br />
<br />
B.bat <br />
@echo off<br />
set str1=%1<br />
set str2=%2<br />
set str3=%str1%,%str2%<br />
<br />
Expected that B.bat return %str3% (means 1,2,3,4,5,6,7,8,9) back to A.bat file So that A.bat used the result for further processing.
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I have two batch files A.bat and B.bat. A.bat is calling to B.bat.
B.bat is doing some processing, and return back the result to A.bat. How A.bat can accept the return?

A.bat 
@echo off
set str1=1,2,3,4,5
set str2=6,7,8,9
call B.bat %str1% %str2%

B.bat 
@echo off
set str1=%1
set str2=%2
set str3=%str1%,%str2%

Expected that B.bat return %str3% (means 1,2,3,4,5,6,7,8,9) back to A.bat file So that A.bat used the result for further processing.

Return result to caller batch file

Batch files are text files containing a script of commands that are executed by the command interpreter on DOS, OS/2 and Windows systems. Most commonly, they are used to perform a series of functions that are repeated -- copying a set of files created daily with one step, for example.