QT Launch External Program

Brief Introduction

Qprocess can be used to start external programs and interact with them.

To start a process by calling start (), the parameter contains the name of the program and the command-line arguments, as a single string of qstringlist.

Alternatively, you can use Setprogram () and setarguments () to run, and then call Start () or open ().

Brief interface Example cmd start cmd cmd with parameter cmd get return value putty telnet WINSCP remote file transfer pipeline error handling parameter arguments get environment variable

Interface

Start () Launch external program

Readallstandarderror () Get all the data from the standard error

Readallstandardoutput () Get all data from standard output

Write () inherits from Qiodevice

Close () inherits from Qiodevice

In addition to this, qprocess also contains static member functions:

Execute () starts a process, and then waits for the process to end.

Startdetached () starts a process and then makes it out of the process's parent-child relationship with the current process. 

Example cmd start cmd

Qprocess process (this);
Process.startdetached ("cmd.exe");

cmd with Parameters

Use cmd to delete local files

Qprocess process (this);
Process.Start ("cmd.exe");
Process.write ("del e:\\a.txt\n\r");
Process.write ("exit\n\r");
Process.waitforfinished ();
Process.close ();

cmd Gets the return value

Use CMD to view network conditions

qstringlist arguments;
Arguments << "/C" << "ping www.baidu.com";

Qprocess process (this);
Process.Start ("cmd.exe", arguments);
Process.waitforstarted ();
Process.waitforfinished ();
QString strresult = Qstring::fromlocal8bit (Process.readallstandardoutput ());

Qmessagebox MsgBox (this);
Msgbox.settext (strresult);
Msgbox.exec ();

Putty Telnet

QString program = "E:/putty.exe";

qstringlist arguments;
arguments<< "-PW" << "Wang" << QString ("%1@%2"). Arg ("root"). Arg ("172.18.5.73") << "a";

Qprocess *process = new Qprocess (this);
Process->setprocesschannelmode (qprocess::separatechannels);
Process->setreadchannel (qprocess::standardoutput);
Process->start (program, arguments, Qiodevice::readwrite);

winscp Remote File transfer

QString program = Qcoreapplication::applicationdirpath () + "/winscp/winscp.exe";

qstringlist arguments;
Arguments << QString ("%1:%2@%3:%4"). Arg ("root"). Arg ("Wang"). Arg ("172.18.5.73"). Arg;

Qprocess *process = new Qprocess (this);
Process->setprocesschannelmode (qprocess::separatechannels);
Process->setreadchannel (qprocess::standardoutput);
Process->start (program, arguments, Qiodevice::readwrite);

Piping

A process's standard output stream to the standard input of the target process.

Command1 | Command2

Can be implemented with the following code:

Qprocess Process1;
Qprocess Process2;

Process1.setstandardoutputprocess (&PROCESS2);

Process1.start ("Command1");
Process2.start ("Command2");

Error Handling

Initiates an external program that, when an error occurs, can describe the type of error that occurred based on the specified error.

connect (Process, SIGNAL (Error (qprocess::P rocesserror)), this, SLOT (Processerror (qprocess

::P rocesserror))); void Processerror (qprocess::P rocesserror error) {switch (error) {case Qprocess::failedtostart:qmessa
        Gebox::information (0, "Tip", "Failedtostart");
    Break
        Case qprocess::crashed:qmessagebox::information (0, "Tip", "Crashed");
    Break
        Case qprocess::timedout:qmessagebox::information (0, "Tip", "timedout");
    Break
        Case qprocess::writeerror:qmessagebox::information (0, "Tip", "Writeerror");
    Break
        Case qprocess::readerror:qmessagebox::information (0, "Tip", "Readerror");
    Break
        Case qprocess::unknownerror:qmessagebox::information (0, "Tip", "Unknownerror");
    Break
        Default:qmessagebox::information (0, "Tip", "Unknownerror");
    Break }
}

Assuming there is no corresponding external program, the error type Qprocess::failedtostart is returned. parameter Arguments

Take Putty Telnet as an example, putty can use the command line putty [-PW password] user@ip to connect.

So where the middle spaces are separated by a single string using arguments:

qstringlist arguments;
arguments<< "-PW" << "Wang" << QString ("%1@%2"). Arg ("root"). Arg ("172.18.5.73");

Other parameters are similar.

Qprocess process;
Process.Start ("del/s *.txt");
Equivalent to Process.Start ("Del", Qstringlist () << "/S" << "*.txt");

Get Environment Variables

Returns the environment variable that invokes the process as a list of key-value pairs.

Qstringlist environment =  qprocess::systemenvironment ();
Environment = {"Path=/usr/bin:/usr/local/bin", "User=greg", "Home=/home/greg"}