Break Loop infinite

[ngusaomanoi]

Hi All,
I have a Loop Infinite.

for /L %%n in (1,0,10) do (
echo "infinite\n"
if exist "%~dp0\Parts\file.xml"
(
//I want break here
)
)
anybody give me syntax break in batch file.

[foxidrive]

What do you mean break? Control C?

Explain what you are trying to do...

[ngusaomanoi]

I use batch file no use console.
Thanks.

[foxidrive]

Explain what you are trying to do...

See above.

For example you can put in a statement and check for the existence of another file, and branch out of the loop.

It depends on what you want to do.

[Squashman]

We had a thread a few months back about breaking out of FOR /L loops. Gotta dig that up.

[Aacini]

This question was extensively discussed at infinite loop with break condition topic, and the last solution is here

Antonio

[tomato]

To break in for-loop, use "goto ~ label" statement as followings.

for /L %%n in (1,0,10) do (
echo "infinite\n"
if exist "%~dp0\Parts\file.xml" (
goto :break
)
)
:: label
:break

[Aacini]

@tomato: Please, test the previous program by yourself: it never ends and requires a Ctrl-C cancellation!

(perhaps you should read the referred topic so you know what we are talking about)

Antonio

[tomato]

@Antonio
sorry for my mistake. I did not watch the code carefully.

@ngusaomanoi
In your for-loop,

(1, 0, 10) -> (start, step, end)

because the step is 0, the start(=1) cannot reach the end(=10).
Therefore it causes an infinite loop.

Replace step to any other value greater than 0.
eg. (1, 1, 10)

[Liviu]

(1, 0, 10) -> (start, step, end)

because the step is 0, the start(=1) cannot reach the end(=10).
Therefore it causes an infinite loop.

Right. That's probably why the title of this thread is "Break Loop infinite"

FWIW "goto :break" doesn't really work for finite loops, either, even though it may appear to. What happens is that the body of the for loop stops being executed after the goto, but the loop itself unrolls all the way to the end before jumping to the label. For a simple example, save the following as for123.cmd

Code: Select all

@for /l %%i in (1,1,3) do (
  echo %%i
  goto :break
)

:break
@echo done

then run it at a command prompt.

Code: Select all

C:\tmp>for123

C:\tmp>(
echo 1
 goto :break
)
1

C:\tmp>(
echo 2
 goto :break
)

C:\tmp>(
echo 3
 goto :break
)
done

C:\tmp>

Note that the body of the loop is still parsed 3 times, regardless of the goto :break. The actual output in this case is "1" then "done" as probably expected, but if you replace (1,1,3) with (0,0,0) or simply () then the loop becomes infinite, and the "done" line is never reached - which was the topic in point here, and discussed in detail at the links Aacini provided.

Liviu