Why does it takes soo long...?

Anonymous_Banned275

*I am including my code.

My objective is to start a new process and execute "system call".
Such call takes no noticeable time when executed in "terminal".

It QT it takes ESTIMATED time of about 20 -30 seconds. ( I have no implemented the timer) to finish the "new process".

WHY?

I also do not get why it runs the "waiting for..." twice, but that is NOT my main concern for now.


        // run QProcess first time
        time->start();
        QP = new QProcess();
        qDebug() << "DEBUG TRACE start new QProcess();";
        text = "DEBUG TRACE start new QProcess();";
        //TRACE_TextEdit->addItem(text);
        qDebug() << text;
        text = " command ";
        text += command;
        // add file
        text += " | tee /tmp/temp";
        qDebug() << text;

        QP->start("/bin/sh", QStringList() << "-c" << command);
        if(QP->Running)
        {
            text = "QProcess running..";
            qDebug() << text;
        }
//#ifdef BYPASS
        if(QP->waitForFinished())
        {
            text = "QProcess finished";
            qDebug() << text;
        };
        time->elapsed();
//#endif

        text = "read stadard error ";
        qDebug() << text;
        text = "read stadard output ";
        qDebug() << text;

        text = QP->readAllStandardOutput();

        qDebug() << text;
        return text;

Debug output

"setup Bluetooth virtual serial port \n void MainWindow_Bluetooth::on_actionBluetooith_virtiual_port_triggered()"
"Process command...QString BT_Utility_Library::ProcessCommand(char *)"
DEBUG TRACE start new QProcess();
"DEBUG TRACE start new QProcess();"
" command bluetoothctl | tee /tmp/temp"
"QProcess running.."
"read stadard error "
"read stadard output "
"Waiting to connect to bluetoothd...\r\u001B[0;94m[bluetooth]\u001B[0m# \r\r\u001B[0;94m[bluetooth]\u001B[0m# \r \rAgent registered\n\u001B[0;94m[bluetooth]\u001B[0m# \r \r[\u0001\u001B[0;93m\u0002CHG\u0001\u001B[0m\u0002] Controller 00:50:B6:80:4D:5D Pairable: yes\n\u001B[0;94m[bluetooth]\u001B[0m# \r \r[\u0001\u001B[0;93m\u0002CHG\u0001\u001B[0m\u0002] Controller 00:15:83:15:A2:CB Pairable: yes\n\u001B[0;94m[bluetooth]\u001B[0m# "
"Process command...QString BT_Utility_Library::ProcessCommand(char *)"
DEBUG TRACE start new QProcess();
"DEBUG TRACE start new QProcess();"
" command bluetoothctl | tee /tmp/temp"
"QProcess running.."
"read stadard error "
"read stadard output "
"Waiting to connect to bluetoothd...\r\u001B[0;94m[bluetooth]\u001B[0m# \r\r\u001B[0;94m[bluetooth]\u001B[0m# \r \rAgent registered\n\u001B[0;94m[bluetooth]\u001B[0m# "
"Waiting to connect to bluetoothd...\r\u001B[0;94m[bluetooth]\u001B[0m# \r\r\u001B[0;94m[bluetooth]\u001B[0m# \r \rAgent registered\n\u001B[0;94m[bluetooth]\u001B[0m# \r \r[\u0001\u001B[0;93m\u0002CHG\u0001\u001B[0m\u0002] Controller 00:50:B6:80:4D:5D Pairable: yes\n\u001B[0;94m[bluetooth]\u001B[0m# \r \r[\u0001\u001B[0;93m\u0002CHG\u0001\u001B[0m\u0002] Controller 00:15:83:15:A2:CB Pairable: yes\n\u001B[0;94m[bluetooth]\u001B[0m# "
"Failed Controller"
"Agent registered"
09:39:59: /mnt/RAID_124/PROJECTS_FEB26_LIB/mdi/MDI exited with code 0

Pl45m4

@AnneRanch said in Why does it takes soo long...?:

text = " command ";
text += command;
// add file
text += " | tee /tmp/temp";
qDebug() << text;
QP->start("/bin/sh", QStringList() << "-c" << command);

What's the reason to actually write "command" to command line?
Don't you just want to call bluetoothctl and pipe it with tee /tmp/temp?

Edit:
Does it make any difference, if you don't explicitly use command bluetoothctl?

Anonymous_Banned275

@Pl45m4 I have removed the stupid mistake of adding ":command" text, removed the redirection to temp file and it still takes forever and rums twice.

I never see "fished" ....

Here is the full debug op0utput

11:50:29: Starting /mnt/RAID_124/PROJECTS_MAR1_/mdi/MDI...
Warning: Ignoring XDG_SESSION_TYPE=wayland on Gnome. Use QT_QPA_PLATFORM=wayland to run on Wayland anyway.
"void MainWindow::menu_slot_indexed(int)"
"add it as subwindow "
"setup Bluetooth virtual serial port \n void MainWindow_Bluetooth::on_actionBluetooith_virtiual_port_triggered()"
"Process command...QString BT_Utility_Library::ProcessCommand(char *)"
DEBUG TRACE start new QProcess();
"DEBUG TRACE start new QProcess();"
"QProcess running.."

why is it running this  BEFORE "finished" ??


"read stadard error "
"read stadard output "
"Waiting to connect to bluetoothd...\r\u001B[0;94m[bluetooth]\u001B[0m#                                                                              \r\r\u001B[0;94m[bluetooth]\u001B[0m# \r                        \rAgent registered\n\u001B[0;94m[bluetooth]\u001B[0m# \r                        \r[\u0001\u001B[0;93m\u0002CHG\u0001\u001B[0m\u0002] Controller 00:50:B6:80:4D:5D Pairable: yes\n\u001B[0;94m[bluetooth]\u001B[0m# \r                        \r[\u0001\u001B[0;93m\u0002CHG\u0001\u001B[0m\u0002] Controller 00:15:83:15:A2:CB Pairable: yes\n\u001B[0;94m[bluetooth]\u001B[0m# "
"Process command...QString BT_Utility_Library::ProcessCommand(char *)"
DEBUG TRACE start new QProcess();
"DEBUG TRACE start new QProcess();"
"QProcess running.."
"read stadard error "
"read stadard output "
"Waiting to connect to bluetoothd...\r\u001B[0;94m[bluetooth]\u001B[0m#                                                                              \r\r\u001B[0;94m[bluetooth]\u001B[0m# \r                        \rAgent registered\n\u001B[0;94m[bluetooth]\u001B[0m# "
"Waiting to connect to bluetoothd...\r\u001B[0;94m[bluetooth]\u001B[0m#                                                                              \r\r\u001B[0;94m[bluetooth]\u001B[0m# \r                        \rAgent registered\n\u001B[0;94m[bluetooth]\u001B[0m# \r                        \r[\u0001\u001B[0;93m\u0002CHG\u0001\u001B[0m\u0002] Controller 00:50:B6:80:4D:5D Pairable: yes\n\u001B[0;94m[bluetooth]\u001B[0m# \r                        \r[\u0001\u001B[0;93m\u0002CHG\u0001\u001B[0m\u0002] Controller 00:15:83:15:A2:CB Pairable: yes\n\u001B[0;94m[bluetooth]\u001B[0m# "
"Failed Controller"
"Agent registered"
11:51:57: /mnt/RAID_124/PROJECTS_MAR1_/mdi/MDI exited with code 0

Pl45m4

@AnneRanch said in Why does it takes soo long...?:

I have removed the stupid mistake of adding ":command" text

command is an actual CL command, but I dont think it's needed here to call bluetoothctl.

https://askubuntu.com/questions/512770/what-is-the-bash-command-command

"Failed Controller"

Note this error, which comes from bluetoothctl output.

Anonymous_Banned275

@Pl45m4 Partially solved. Had two instances of QProcess...
Will add real time timer to see the actual processing time. Still feels sluggish.

Anonymous_Banned275

@AnneRanch Here is the latest - after fixing few "yser errors" it is still back to the original - why it takes 30 seconds to finish ??

It look s as the QProcess ":finished" is not really monitoring the "finished " but it runs some standard fixed timeout

12:18:01: Starting /mnt/RAID_124/PROJECTS_MAR1_/mdi/MDI...
Warning: Ignoring XDG_SESSION_TYPE=wayland on Gnome. Use QT_QPA_PLATFORM=wayland to run on Wayland anyway.
"void MainWindow::menu_slot_indexed(int)"
"add it as subwindow "
"setup Bluetooth virtual serial port \n void MainWindow_Bluetooth::on_actionBluetooith_virtiual_port_triggered()"
"Process command...QString BT_Utility_Library::ProcessCommand(char *)"
DEBUG TRACE start new QProcess();
"DEBUG TRACE start new QProcess();"
"QProcess running.."

**"QProcess elapsed time 30035"**

"read stadard error "
"read stadard output "
"Waiting to connect to bluetoothd...\r\u001B[0;94m[bluetooth]\u001B[0m#                                                                              \r\r\u001B[0;94m[bluetooth]\u001B[0m# \r                        \rAgent registered\n\u001B[0;94m[bluetooth]\u001B[0m# \r                        \r[\u0001\u001B[0;93m\u0002CHG\u0001\u001B[0m\u0002] Controller 00:50:B6:80:4D:5D Pairable: yes\n\u001B[0;94m[bluetooth]\u001B[0m# \r                        \r[\u0001\u001B[0;93m\u0002CHG\u0001\u001B[0m\u0002] Controller 00:15:83:15:A2:CB Pairable: yes\n\u001B[0;94m[bluetooth]\u001B[0m# "
"Waiting to connect to bluetoothd...\r\u001B[0;94m[bluetooth]\u001B[0m#                                                                              \r\r\u001B[0;94m[bluetooth]\u001B[0m# \r                        \rAgent registered\n\u001B[0;94m[bluetooth]\u001B[0m# \r                        \r[\u0001\u001B[0;93m\u0002CHG\u0001\u001B[0m\u0002] Controller 00:50:B6:80:4D:5D Pairable: yes\n\u001B[0;94m[bluetooth]\u001B[0m# \r                        \r[\u0001\u001B[0;93m\u0002CHG\u0001\u001B[0m\u0002] Controller 00:15:83:15:A2:CB Pairable: yes\n\u001B[0;94m[bluetooth]\u001B[0m# "
"result OK"
"Waiting to connect to bluetoothd...\r\u001B[0;94m[bluetooth]\u001B[0m#                                                                              \r\r\u001B[0;94m[bluetooth]\u001B[0m# \r                        \rAgent registered\n\u001B[0;94m[bluetooth]\u001B[0m# \r                        \r[\u0001\u001B[0;93m\u0002CHG\u0001\u001B[0m\u0002] Controller 00:50:B6:80:4D:5D Pairable: yes\n\u001B[0;94m[bluetooth]\u001B[0m# \r                        \r[\u0001\u001B[0;93m\u0002CHG\u0001\u001B[0m\u0002] Controller 00:15:83:15:A2:CB Pairable: yes\n\u001B[0;94m[bluetooth]\u001B[0m# "
"Controller"
"Agent registered"
12:18:54: /mnt/RAID_124/PROJECTS_MAR1_/mdi/MDI exited with code 0

Anonymous_Banned275

@AnneRanch SOLVED ??

I just realized I have been here before....
Here is the problem
"finished" does NOT monitor the QProcess for "end of story, done" it just waits until preset timeout... ( 30 s default )

waitForReadyRead() actu8ally monitors the QProcess BUT

bluetoothctl FIRST line response is

"Waiting to connect to bluetoothd..."

and
waitForReadyRead() detect that line as " QProcess is done ..."

DEBUG TRACE start new QProcess();
"DEBUG TRACE start new QProcess();"
"QProcess running.."
"QProcess finished"
"QProcess elapsed time 24"
"read stadard error "
"read stadard output "
"Waiting to connect to bluetoothd..."
"Waiting to connect to bluetoothd..."
"result OK"
"Waiting to connect to bluetoothd..."
"Failed Controller"
"Failed Agent registered"
12:49:17: /mnt/RAID_124/PROJECTS_MAR1_/mdi/MDI exited with code 0

SimonSchroeder

@AnneRanch IIRC finished() is a signal that is emitted when the process is actually finished. However, waitForFinished() has a default parameter for 3 seconds. So, after 3 seconds it will just stop waiting. This is most likely now what you want.

JonB

@SimonSchroeder said in Why does it takes soo long...?:

has a default parameter for 3 seconds

The default is 30000 ms == 30 seconds.

Anonymous_Banned275

@SimonSchroeder OK, let's define "process is finished" .
In my case the process task is to execute system command.
The command response is a raw text output - control characters and ASCII .

How does process detects that the command output is done / fished?

( how does QProcess detects ANY "task is finished " ?)

In my opinion - it cannot .

So I ended with this - pseudo code

do
wait for "finshed"
check for "ReadyRead"

did the read text contain desired data
in selected time interval ?

while
no, go back to "do"

or if selected time interval expired without data
exit

JonB

@AnneRanch said in Why does it takes soo long...?:

How does process detects that the command output is done / fished?
( how does QProcess detects ANY "task is finished " ?)
In my opinion - it cannot .

QProcess detects when the process exits, which the OS reports to it. It is not determined by any output the process might or might not produce.

While the process is still running the parent does not get/emit the finished signal and it may see output from the subprocess depending on how the sub-process output code is written.

When the process does finish any remaining output can be read.

Anonymous_Banned275

@JonB So when I actually time my process by monitoring the actual data detected I get something around 500 ms. However , when I set the "finished" back to default ( 30 s) - the QProcess runs full 30 s .

I can probably set the "finished" to an hours and it will wait that long...

It tells me that OS , as you claim, does not generate anything to the QProcess to tell it (OS) is finished.

Your claim and my practical example just do not agree...

JonB

@AnneRanch
Mine isn't a claim, it's how it works. You can also check the Qt source code.

If waitForFinished() takes 30 seconds that tells you the subprocess has not exited. So obviously if you have connected the finished signal you will never get that.

You can verify whether the subprocess you have spawned is still running (while your Qt app is still running) via a suitable ps.

If what you spawn is an "interactive" program which waits for the user to type something it will not finish/exit. If your command is bluetoothctl does that not sit and wait for the user to type into it?

Anonymous_Banned275

@AnneRanch Disregard r my last post... I just recall I have been thru this before and the real "problem" is - the "command" DOES not finishes - it is still running the "script" hence there is nothing to tell OS it is done .
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