Martin that's so kind, thank you. I will investigate OpenProcess and see if I
can make this work.
Ben
On 29/08/2026 12:52, Martin Koob wrote:
Hi,
Rather than *shell()* you can use *open process* in LiveCode to have the
process run asynchronously, get PIDs to monitor progress and kill processes at
a time point. I had a vague idea of how this worked in theory. But, instead
of relying on my rusty brain I opened my trusty ChatGPT (5.6 sol light) and
trying a few different prompts in order to fully understand the process it
produced something that I understand and I think should do what you want. Here
is a list-server friendly summary I asked ChatGPT to make of a much longer chat.
ChatGPT
//////./////.//////./////.//////./////.//////./////.//////./////.//////./////.//////./////.//////./////.//////./////.//////./////.//////./////.//////./////.
This is possible, but a shell process cannot directly call a LiveCode
handler. It must communicate its progress and final result back through
something LiveCode can monitor, such as stdout, a status file, or a
localhost socket. LiveCode then turns that event into a callback message.
The shell() function is synchronous, so calling a long-running command
with shell() will block LiveCode. It can still be used briefly to launch a
properly detached background process and obtain its PID, provided all of
the process’s standard streams are redirected.
The open process command is another possibility. Unlike shell(), open
process starts a process and returns immediately. It can open the process
for reading, writing, both, or neither. LiveCode can also inspect
openProcesses and openProcessIDs. However, open process does not provide
an automatic completion callback, and support for Unix command-line
processes on macOS is limited.
A practical cross-platform design would be:
LiveCode starts a detached worker and records its PID.
The worker writes progress messages to a file or local socket.
LiveCode uses “send monitorJob to me in 100 milliseconds” to check
progress without blocking the UI.
A launcher or watchdog enforces the time limit and terminates the worker
if necessary.
The worker or launcher writes a final status such as success, error, or
timeout, together with the exit code and message.
The LiveCode monitor handler dispatches the appropriate success or error
callback.
For example, the final status might be:
success,0,Completed
error,17,Could not open input file
timeout,124,Process exceeded its time limit
The LiveCode monitoring handler would read that status and dispatch
something such as jobSucceeded or jobFailed. Therefore, the “callback” is
generated by LiveCode after it receives the process result; it is not a
direct call from the shell process.
For simple and reliable jobs, I would use progress and status files. For
frequent or immediate updates, a localhost socket is more event-driven.
Reading stdout from an open process can also work, but care is needed
because a read can block if no output is available, and the child process
may buffer its output.
This is similar to the behavior exposed by tsNet, although tsNet
implements its asynchronous work and callbacks inside an external library.
\\\\\.\\\\\\.\\\\\\\\.\\\\\\.\\\\\.\\\\\\.\\\\\.\\\\\\.\\\\\.\\\\\\.\\\\\.
\\\\\\.\\\\\.\\\\\\.\\\\\.\\\\\\.\\\\\.\\\\\\.\\\\\.\\\\\\.\\\\\.\\\\\\.\\
\\\.\\\\\\.\\\\\\.ChatGPT
If you are interested in the full chat which includes code to implement the
ideas above using Windows( as Ben asked) and a fuller exposition of the
concepts I can upload the full chat where ever you think is best. (I am
pretty sure I can't send it through the use-LiveCode list.)
WARNING: I have not tested this idea out. ChatGPT is fairly good with LiveCode
and pretty solid at creating shell code but it does make syntax errors in
LiveCode at times. I have added rules in my ChatGPT memory to catch some
common ones I have come across e.g. it makes up weird ways to end up repeat
blocks. Correcting it in the chat never had a lasting effect. For example, It
would pick random ways from other programming languages. I had to explicitly
ask it to commit the correct LiveCode way to create repeat loops to memory.
Martin
On Aug 27, 2026, at 11:22 AM, Ben Rubinstein via use-livecode <use-
[email protected]> wrote:
Thanks Bob; but I was hoping to do this in LiveCode.
e.g. is there a way to invoke a shell command to run asynchronously,
returning the PID to LiveCode so that it can be monitored?
On 26/08/2026 16:26, Bob Sneidar via use-livecode wrote:
<https://superuser.com/questions/520527/windows-command-line-time-limit>
superuser.com<https://superuser.com/questions/520527/windows-command-line-
time-limit>
[X]<https://superuser.com/questions/520527/windows-command-line-time-limit>
I just googled it.
Bob S
On Aug 26, 2026, at 02:07, Ben Rubinstein via use-livecode <use-
[email protected]> wrote:
Hello hive mind,
Is there a way from LiveCode to invoke a shell command with a time limit,
to force it to fail after a certain time? (This is on Windows.)
many thanks,
Ben
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