How to start other .exe and return value ?

Reply to How to start other .exe and return value ? on Fri, 21 Jul 2017 08:18:56 GMT

VRonin — Fri, 21 Jul 2017 08:18:56 GMT

I think the main question here is: how does your external application returns the data?

does it exit with a different code for each possible result (it would be unsual but I'm not ruling it out)?
does it print to standard output (the console) the answer? if so in what format?
does it communicate in any other way (shared memory,DBus,TCP,Local Socket, HTTP, FTP, etc)?

Reply to How to start other .exe and return value ? on Thu, 20 Jul 2017 10:00:49 GMT

jsulm — Thu, 20 Jul 2017 10:00:49 GMT

@Taz742 said in How to start other .exe and return value ?:

If my process is run .exe program that has a form we can do emit true or false or QVector ... QList...?
I can not understand how I could do that.

You either use stdout/stdin like shown in my post above. Or you use some kind of IPC (Inter Process Communication). For example shared memory, DBus, ...
See http://doc.qt.io/qt-5/qtcore-ipc-sharedmemory-example.html for shared memory.

Reply to How to start other .exe and return value ? on Thu, 20 Jul 2017 09:57:57 GMT

jsulm — Thu, 20 Jul 2017 09:57:57 GMT

@Taz742 Please read documentation, everything is there.
See http://doc.qt.io/qt-5/qiodevice.html#readyRead, http://doc.qt.io/qt-5/qiodevice.html#write-2, http://doc.qt.io/qt-5/qprocess.html#readAllStandardOutput
There is even an example showing how to do it:

QProcess gzip;
gzip.start("gzip", QStringList() << "-c");
if (!gzip.waitForStarted())
    return false;

gzip.write("Qt rocks!");
gzip.closeWriteChannel();

if (!gzip.waitForFinished())
    return false;

QByteArray result = gzip.readAll();

Reply to How to start other .exe and return value ? on Thu, 20 Jul 2017 09:48:28 GMT

Taz742 — Thu, 20 Jul 2017 09:48:28 GMT

@J.Hilk
If my process is run .exe program that has a form we can do emit true or false or QVector ... QList...?
I can not understand how I could do that.

Reply to How to start other .exe and return value ? on Thu, 20 Jul 2017 09:15:29 GMT

J.Hilk — Thu, 20 Jul 2017 09:15:29 GMT

@Taz742

if you want to keep it simple:

this Signal and this function most likly.

alternatively, QSharedMemory, TCP/UDP ...

Reply to How to start other .exe and return value ? on Thu, 20 Jul 2017 09:03:37 GMT

Taz742 — Thu, 20 Jul 2017 09:03:37 GMT

Let's assume that we are going to perform the operation that can be accomplished or not. I want to understand that.
For small instance, I send a number to another exe and give it back if this number is less than 100.

Reply to How to start other .exe and return value ? on Thu, 20 Jul 2017 08:56:20 GMT

Taz742 — Thu, 20 Jul 2017 08:56:20 GMT

@jsulm
Yes I know how to run another program, but how do I get value from it?
Maybe you give me the right direction

Reply to How to start other .exe and return value ? on Thu, 20 Jul 2017 08:50:09 GMT

jsulm — Thu, 20 Jul 2017 08:50:09 GMT

@Taz742 http://doc.qt.io/qt-5/qprocess.html