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If I run these commands:

... geany --new-instance --no-msgwin --no-session --no-terminal -c pathtoconfig/ & pid=$! echo $pid wmctrl -lp read -p "waiting..." ...

the resulting PID does not match that of the geany process launched. But if a sleep 1 command is inserted before reading the PID (after the geany line), then the PID is correct. The reason for this is that windowing takes some time, so wmctrl -lp provides preliminary information which does not much precisely the right PID. What would be the best way to wait for geany to complete launching before the new window has stabilized and wmctrl is aware of it?

Update: - Run on Lubuntu 16.04 / HP ProBook 6360b.

  • Actual PID for comparison was obtained with wmctrl -lp that includes PID in the list.

  • PID is fetched correctly by $!, what takes some time to update is the one provided by wmctrl -lp, that is different after some time (some 0.27s for geany, some 0.16s for leafpad), as if the window manager would take some time to update the PID.

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  • Can't reproduce this behaviour. Can you try run the geany this two ways: geany & and geany --new-instance --no-msgwin --no-session --no-terminal &. Did the problem remained? Commented Jul 23, 2017 at 15:18
  • @MiniMax strangely enough, yes and no. In a battery of tests, have tried the original configuration (doesn't get the correct PID), and then the simplified one, only geany & (it does get the correct PID). Then tried several alternatives, removing some options (doesn't get the correct PID), and finally the simplified one again (and now, does NOT get the correct PID). This was done isolating the piece of code, to make sure that it only relies on launching geany. Commented Jul 23, 2017 at 22:12
  • Can you try another program the same way? May be Netbeans or Libreoffice. I tried Netbeans, it was launching about 10 second, but both PIDs the same. I think geany launching time, does not matter because of how fork–exec works. And another helpful answer about & operator: process in the background. By the way, how you get second PID for comparing? Commented Jul 23, 2017 at 23:04
  • @MiniMax Trying with geany & the PID after settling is 11078, $! got 11118, with leafpad was 11078, and $! got 11173. In both cases, the PID matches perfectly when sleep 1 is added. So, in principle it doesn't seem to be related to launching time, but waiting for some time actually helps. Commented Jul 24, 2017 at 7:33
  • @MiniMax To be more precise, geany & will work fine for a delay of 0.27s, while leafpad & does work for delays over 0.16s. Something is going on after the program is launched. (Technical data added to the question.) Commented Jul 24, 2017 at 7:46

1 Answer 1

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xdotool search --sync --pid "$PID" will do exactly, what you want. I found this method here

--sync - Block until there are results. This is useful when you are launching an application and want to wait until the application window is visible.

Template:

#!/bin/bash geany & PID=$! if xdotool search --sync --pid "$PID" > /dev/null; then # if window with the specific PID has appeared # then doing something here fi

Note:

Doesn't work with some applications, Netbeans for example, because of this:

--pid PID - Match windows that belong to a specific process id. This may not work for some X applications that do not set this metadata on its windows.

If change --pid "$PID" to --name netbeans or --class netbeans it works too.

Working example:

This script calculate delay in milliseconds, between launching geany & and the geany's window appearing.

#!/bin/bash geany & PID=$! time_start=$(date '+%s%3N') if xdotool search --sync --pid "$PID" > /dev/null; then time_end=$(date '+%s%3N') time_interval=$((time_end - time_start)) printf "%'d ms\n" "$time_interval" fi

Output:

$ ./delay_calculate.sh 553 ms
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