How we can run Linux command from qt code?

jsulm

@Wasee Did you do what @JonB mentioned: "provided you have first typed that command into a bash shell to verify it works correctly"?
So, does it work if you do it in terminal?

jsulm

This post is deleted!

JonB

@Wasee said in How we can run Linux command from qt code?:

but still not changing TX_LO_frequency value. why?

Did you even at least check the return result of the open() for yourself? For all I know you do not have permission to write to that file. This is part of what doing development involves....

@jsulm

Also I would not write a string but a number:

That's fine, but it's not what the OP's echo 24250000 > out_altvoltage1_TX_LO_frequency would do (treat anything as a number), which I was trying to copy. In fact I think Linux echo will append a newline, so the OP may need to do that too.

Wasee

@JonB said in How we can run Linux command from qt code?:
echo 24250000 > out_altvoltage1_TX_LO_frequency this command run in terminal and change the value on device. But not changing from qt code.

jsulm

@Wasee said in How we can run Linux command from qt code?:

change the value on device

Without sudo?

Please add error handling to your code: print error message if f.open(...) fails.

Wasee

@jsulm Hi;
Yes without sudo in terminal its changing value. No error of device open its not returning.
thanks

JonB

@Wasee

Did you add the error checking code I advised?
Did you try appending the newline I advised?

Wasee

@JonB said in How we can run Linux command from qt code?:

QFile f("/sys/bus/iio/devices/iio:device1/out_altvoltage1_TX_LO_frequency");
if (f.open(QIODevice::WriteOnly))
{
qint64 count = f.write("24250000");
Q_ASSERT(count > 0);
f.close();
}

how I can pass variable instead of 24250000.

Wasee

@JonB Thanks for your appreciated help!
Your suggestion of QFile is working fine now.

QFile f("/sys/bus/iio/devices/iio:device1/out_altvoltage1_TX_LO_frequency");
if (f.open(QIODevice::WriteOnly))
{
    qint64 count = f.write("2425000000");
    Q_ASSERT(count > 0);
    f.close();
}

The value 2425000000 is coming from a variable which can be change any time. I need to pass this value as a variable instead of constant 2425000000.
thanks

KroMignon

@Wasee said in How we can run Linux command from qt code?:

The value 2425000000 is coming from a variable which can be change any time. I need to pass this value as a variable instead of constant 2425000000.
thanks

Are you joking???
Do you really don't have any idea how to do this simple stuff?
It is so complicated to create a string and write it to a file?
What did you try to do?

JonB

@Wasee
You must convert your (integer) variable to a string. QIODevice::write() accepts either a const char * or a const QByteArray & for the string to write. You can use either QString::number() or QByteArray::number() to convert a number to a string/byte array to pass to write(), as you please.