QT New Process

Qt qprocess

As a framework for almost language-level changes to C + +, the package is similar to cocoa, and, in fact, it feels like Qt has changed the language characteristics of C + + from cocoa to objective C, but the difference is that QT does not dominate the C + + world.
Test1:

#include <QtCore/QCoreApplication>
#include <QtCore/QProcess>
#include <QtCore/QStringList>

int main (int argc, char *argv[])
{
QString program = "Cat";
Qstringlist arguments;
Arguments << "A" << "B";

Qprocess *myprocess =NewQprocess ();
Myprocess->start (program, arguments);
Myprocess->waitforfinished ();
Qbytearray output = Myprocess->readallstandardoutput ();
printf ("%s", (const char*) output);

return0;
}

Qprocess is the process class for QT encapsulation, which needs to be specifically explained by the use of QT4 and Qt3 is different. And, there is a problem because QT is now almost pure GUI-oriented interface library, so qprocess default is the command line does not output, here turn a bend, read out the output, and then output with printf.

Test2:

#include <QtCore/QCoreApplication>
#include <QtCore/QProcess>
#include <QtCore/QStringList>

int main (int argc, char *argv[])
{
QString program = "Cat";
Qstringlist arguments;
Arguments << "A" << "B";

Qprocess *myprocess =NewQprocess ();
Myprocess->setstandardoutputfile ("C");
Myprocess->start (program, arguments);
Myprocess->waitforfinished ();

return0;
}
But looking at the example, what it feels like. Personal feeling Qt deserves to be a special API, relying on the API to eat and rely on the sale of hardware for the company is not the same, API design is just right, concise introduction, and, most importantly, enough.

TEST3:


#include <QtCore/QCoreApplication>
#include <QtCore/QProcess>
#include <QtCore/QStringList>

int main (int argc, char *argv[])
{
QString program = "/bin/cat";
Qstringlist arguments;
Arguments << "A" << "B";

Qprocess *myprocess =NewQprocess ();
Qprocess *outprocess =NewQprocess ();
Myprocess->setstandardoutputprocess (outprocess);

Myprocess->start (program, arguments);
Outprocess->start (program);
Myprocess->waitforfinished ();
Outprocess->waitforfinished ();

Qbytearray output = Outprocess->readallstandardoutput ();
printf ("%s", (const char*) output);
return0;
}

In general, QT does not design pipe corresponding classes, but, for a function can solve the task, it is obvious that the use is more simple, like cocoa, such a simple concept of the corresponding encapsulation, in fact, there is excessive design suspicion .... In fact, Nspipe is also 2, 3 functions, and, as shown in this example, in fact, in addition to a useful, nspipe more than a few of the many are because of the nspipe only appear function .... In sorrow ....

General Table

Usage/code amount	Test1	Test2	Test3
SHELL	Single-line 5 characters	line 7 characters	line 9 characters
C runtime  Library ' s system	5 lines	5 lines	5 lines
Python ' s os.system	2 lines	2 lines	2 lines
Win32 API winexec/shellexecute	6 lines	6 lines	type restrictions
Win32 API CreateProcess	16 lines	16 lines	type restrictions
Objective C with Cocoa	15 lines	23 lines	23 lines
Qt qprocess	16 lines	15 lines	20 lines