Fork: Difference between revisions

=={{header|Batch File}}==

While you cannot fork into asynchronous subroutines conventionally, there are workarounds involving the <code>start</code> command.

<lang dos>

@echo off

if "%1" neq "" goto %1 || echo Not a valid subroutine

echo Starting mySubroutine1

start "" "%~n0" mySubroutine1

echo.

echo Starting mySubroutine2 6 3

start "" "%~n0" mySubroutine2 6 3

echo.

echo Starting mySubroutine3

start "" "%~n0" mySubroutine3

echo.

:: We wait here for the subroutines to run, but they are running asynchronously

timeout /t 1

for /l %%i in (1,1,3) do (

for /f "tokens=*" %%j in (output%%i.txt) do (

set output%%i=%%j

del output%%i.txt

)

)

echo.

echo.

echo Return values

echo ----------------------------

echo mySubroutine1: %output1%

echo mySubroutine2: %output2%

echo mySubroutine3: %output3%

pause>nul

exit

:mySubroutine1

echo This is the result of subroutine1 > output1.txt

exit

:mySubroutine2

set /a result=%2+%3

echo %result% > output2.txt

exit

:mySubroutine3

echo mySubroutine1 hasn't been run > output3.txt

if exist output1.txt echo mySubroutine1 has been run > output3.txt

exit

</lang>

Output:

<pre>

Starting mySubroutine1

Starting mySubroutine2 6 3

Starting mySubroutine3

Waiting for 0 seconds, press a key to continue ...

Return values

----------------------------

mySubroutine1: This is the result of subroutine1

mySubroutine2: 9

mySubroutine3: mySubroutine1 has been run

</pre>