Hi Alan,
you can use this (before exec):
setOption("WaitForCompletion", false);
to immediately continue the macro after exec, without waiting.
https://imagej.net/ij/developer/macro/functions.html#setOption
Michael
________________________________________________________________
On 18.02.26 13:52, Alan Hewat wrote:
Thanks again Fred. I can now launch my application from an imageJ macro
with a buld.bat file using
*exec("cmd /c start \"cmdWindow\" build.bat");*
*But now my macro script waits for my application and cmdWindow to close
before continuing.*
How can I launch my application with exec(...) and immediately continue
with my macro script without waiting ?
Alan.
On Tue, 10 Feb 2026 at 22:23, Fred Damen <[email protected]> wrote:
To be pedantic... The strings(s) that you are passing to be executed may
(are) not the parameters that are actually received (argv) by the program
that actually gets executed: executing 'echo' as the executable will show
you what actually made it to the executable program.
Enjoy,
Fred
On Tue, February 10, 2026 3:23 am, Alan Hewat wrote:
*Thanks Rob.* Yes, the backslash \ is a character that escapes the
following character. I used backslashes historically but will try
forward
slashes with my current modern installation.
*Fred, that's brilliant !!!!!!*
exec("cmd /c start \"\" build.bat");
Solves my problem ! I had already tried that, but without the double ""
(escaped) which opens a new *persistent *untitled cmd window. My previous
attempt, based on the examples in
https://wsr.imagej.net/macros/ExecExamples.txt also opened a new cmd
window
but closed it immediately, and perhaps that was the problem. I use
print()
to check the strings I pass to exec().
*Now, to be tidy, I just need to close that cmd window, after perhaps
waiting a moment. *But I'm very happy that I can finally launch SharpCap
with Python scripting from an imageJ script.
Thanks also for the explanation of how exec() works. It was probably
quite
difficult to implement, having to pass parameters through several
systems.
It's perhaps still not quite perfect, which to my mind would mean that
anything that worked in a Windows cmd shell or .bat file worked in exec,
and that exec itself would parse the string. At least, the stated exec()
requirement to use comma separated arguments when there are spaces in the
cmd string, like
exec("cmd", "/c", "start", "excel.exe", path);
no longer seems necessary.
Thanks again to all who responded, suggested new ideas, and solved my
problem. Alan.
On Tue, 10 Feb 2026 at 06:26, Fred Damen <[email protected]> wrote:
Greetings,
A slightly more complicated explanation...
ImageJ's macro function exec passes its parameters to JVM, which passes
its parameters to posix system call, which requests the OS to execute an
executable. At each stage things are manipulated. System shell commands
are not actually executables. You need to pass your shell command (.bat)
to an executable (cmd) to execute it.
exec("cmd /c start \"\" build.bat");
see:
https://stackoverflow.com/questions/615948/how-do-i-run-a-batch-file-from-my-java-application
second answer.
If you want to try and figure out what is going on and resolve the
issue,
try and execute the 'echo' command with your command as its parameters;
echo simply displays its parameters. This will be frustrating and
enlightening, although it may help...
Fred
On Mon, February 9, 2026 9:50 am, Alan Hewat wrote:
Thanks Fred.
Unfortunately *ImageJ exec() doesn't run Windows .bat files as
expected
either :-(*
I have a simple .bat file containing one line, that *executes without
error
when I double-click it in Windows*
"C:\Program Files\SharpCap 4.1 (64 bit)\SharpCap.exe" /language=fr
It launches SharpCap <https://docs.sharpcap.co.uk/4.1/>, a popular
imaging
application for astronomers, with a command-line argument that
specifies
the language
If instead I execute it within an imageJ script with
status = exec("C:\Program Files\SharpCap 4.1 (64 bit)\SharpCap.exe"
/language=fr);
It launches SharpCap but the in-line argument disables SharpCap's own
IronPython script with a "codepage___0" error.
(It does work without the in-line argument, and I want to input more
complicated arguments than the trivial /language).
Other users have reported similar problems and it was suggested
<https://forums.sharpcap.co.uk/viewtopic.php?t=6762>that the code
page
or
environment variables may be set differently.
This problem occurs however I try to execute SharpCap with exec(),
e.g.
https://wsr.imagej.net/macros/ExecExamples.txt
There is a nice example
<https://imagej.net/ij/macros/tools/VideoCaptureTool.txt> of using
exec()
with command-line arguments to record and playback VirtualDub video
That works for me, but doesn't help me understand my problem.
*So is there any other way of launching a Windows process from an
imageJ
macro other than exec() ?*
Regards, Alan.
On Mon, 9 Feb 2026 at 05:45, Fred Damen <[email protected]> wrote:
Greetings,
Generally when I need to run a command line program from within a
program
I am writing and the passing of arguments becomes to frustrating (as
there
are many layers of retranslating the command syntax), I write a
command
line command in the OS(es) native macro language, .bat/.cmd in your
case.
Then the only thing that I need to get correct in the calling program
is
executing the OS macro command itself - which you seem to have
accomplished.
Enjoy,
Fred
On Sun, February 8, 2026 3:22 am, Alan Hewat wrote:
SharpCap <https://docs.sharpcap.co.uk/4.1/> is a popular
astronomical
imaging application and can be launched from a Windows cmd shell
with
a command-line
argument
<https://docs.sharpcap.co.uk/4.0/34_CommandLineArguments.htm>,
like this:
C:\Users\alanh>"..\\..\\Program Files\\SharpCap 4.1 (64
bit)\\SharpCap.exe"
/runscript d:\\cameraList.py
This correctly launches SharpCap to run a Python script
cameraList.py
to
list available cameras (or whatever else is requested).
ImageJ has an exec() function
<https://wsr.imagej.net/developer/macro/functions.html#E> that can
be
used
to launch applications from an imageJ script. The following
launches
SharpCap, but apparently doesn't pass the /runscript argument
correctly
because SharpCap scripting reports an error and doesn't work.
SharpCap = getDirectory("startup")+"..\\..\\Program Files\\SharpCap
4.1
(64
bit)\\SharpCap.exe";
status=exec (SharpCap+" /runscript d:\\cameraList.py");
Guided by the exec() function
<https://imagej.net/ij/macros/ExecExamples.txt> examples, I tried
instead:
status=exec("cmd", "/c", "start", SharpCap, " /runscript", "
d:\\cameraList.py" );
but an error that "*Windows can't find /runscript*" is returned as
if
it
thinks */runscript* is an application.
Replacing */runscript* with the application *SharpCap* as below
works,
but
I don't understand why
status=exec("cmd", "/c", "start", SharpCap, SharpCap, "
/runscript", "
d:\\cameraList.py" );
That launches SharpCap, and no error is reported, but the script is
not
executed.
*The last attempt seems to be close to working, but I must have
made
some
mistake in the exec() syntax.*
The latest versions of imageJ and Win-11 were used. Any suggestions
would
be appreciated. Alan.
--
*_______________________________*
Dr Alan Hewat, NeutronOptics
Grenoble, FRANCE (from computer)
[email protected]
+33.476984168 VAT:FR79499450856
http://NeutronOptics.com/hewat <http://neutronoptics.com/hewat>
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*_______________________________*
Dr Alan Hewat, NeutronOptics
Grenoble, FRANCE (from computer)
[email protected]
+33.476984168 VAT:FR79499450856
http://NeutronOptics.com/hewat <http://neutronoptics.com/hewat>
_______________________________
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*_______________________________*
Dr Alan Hewat, NeutronOptics
Grenoble, FRANCE (from computer)
[email protected]
+33.476984168 VAT:FR79499450856
http://NeutronOptics.com/hewat <http://neutronoptics.com/hewat>
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