QProcess and the command line

[auba]

First to say - on linux, I dont have any problems. I use QProcess to start everything and it works.

First trap - Windows. I can start anything, but for tools using the shell. QProcess::start does neither start cmd.exe (with complete path) nor any tool from cygwin (mc.exe, vi.exe, bash.bat). The only way to get a command line is to use QProgress::startDetached. But then I don't have any chance to set the environment of the shell...

Second Trap - Mac. When my app is already started within the bash, and it starts another bash command, the new shell is opend within the window of the starting shell When the app is started from the dock, starting a command line does nothing at all. Neither QProcess::start nor QProcess::startDetached opens any window at all.

Any suggesgion is welcome

[wysota]

Could you try restating what your questions are? I can see descriptions of the problems but I don't know what you are really asking about.

[auba]

Ok, after mentioning the symptoms, here's the short question: how can I start on the Mac a new bash shell with

QProcess proc;
QStringList args;
proc->start("bash", args);

?

(Same question for vi)

And how can I do the same on Win32?

[spirit]

works fine under Windows

QProcess::startDetached("cmd.exe");

QProcess::startDetached("cmd.exe");

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did not test under other platforms, but I think it should work.

[auba]

Yes, it is on win32 the only way to start cmd. But how can I change the environment then?

(On Mac, is does not work at all)

[auba]

Please, can someone tell me how I can start a new bash shell with QProcess?

[caduel]

really just a shell, or terminal like rxvt or konsole running a bash?

[nightghost]

Set the environment before. The Environment of the process is inherited to its children (here: the command you want to start with QProcess)

We're using this code to archive it (Works under Windows, Linux and OSX)

// header
enum EnvironmentSetOperationResult {
  CouldSetEvironmentVariable = 0,
  FailedToSetEnvironmentVariable = -1
};
 
// cpp
 
#include <cstdlib>
 
#ifdef Q_WS_WIN
// this is needed for the environment functions. Else the function will use unicode
// and will not work with char*
#undef UNICODE
#include <windows.h>
#endif
 
// [...]
 
void Environment::set(const QString& key, const QString& value) {
    // attention!
    //linux   0 == success, -1 == error
    //windows 0 == error,   !0 == success
 
	int num_error = FailedToSetEnvironmentVariable;
 
	QByteArray key_ba = key.toLatin1();
	QByteArray value_ba = value.toLatin1();
 
#ifdef Q_WS_WIN
	if(value.isNull()) {
	  num_error = SetEnvironmentVariableA((LPCSTR) key.toAscii().constData(), NULL);
	} else {
	  num_error = SetEnvironmentVariableA((LPCSTR) key.toAscii().constData(), (LPCSTR) value.toAscii().constData());
	}
	num_error = (num_error == 0 ? FailedToSetEnvironmentVariable : CouldSetEvironmentVariable);
#else
	const int overwrite_variable = 1;
	num_error = setenv(key_ba.constData(), value_ba.constData(), overwrite_variable);
#endif
	if (num_error == FailedToSetEnvironmentVariable)		{
		qDebug() << "Environment::set(): Could not set'" << key << "' to '" << value << "'";
	}
}

// header
enum EnvironmentSetOperationResult {
  CouldSetEvironmentVariable = 0,
  FailedToSetEnvironmentVariable = -1
};

// cpp

#include <cstdlib>

#ifdef Q_WS_WIN
// this is needed for the environment functions. Else the function will use unicode
// and will not work with char*
#undef UNICODE
#include <windows.h>
#endif

// [...]

void Environment::set(const QString& key, const QString& value) {
    // attention!
    //linux   0 == success, -1 == error
    //windows 0 == error,   !0 == success

	int num_error = FailedToSetEnvironmentVariable;

	QByteArray key_ba = key.toLatin1();
	QByteArray value_ba = value.toLatin1();

#ifdef Q_WS_WIN
	if(value.isNull()) {
	  num_error = SetEnvironmentVariableA((LPCSTR) key.toAscii().constData(), NULL);
	} else {
	  num_error = SetEnvironmentVariableA((LPCSTR) key.toAscii().constData(), (LPCSTR) value.toAscii().constData());
	}
	num_error = (num_error == 0 ? FailedToSetEnvironmentVariable : CouldSetEvironmentVariable);
#else
	const int overwrite_variable = 1;
	num_error = setenv(key_ba.constData(), value_ba.constData(), overwrite_variable);
#endif
	if (num_error == FailedToSetEnvironmentVariable)		{
		qDebug() << "Environment::set(): Could not set'" << key << "' to '" << value << "'";
	}
}

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[auba]

really just a shell, or terminal like rxvt or konsole running a bash?

I want to start the bash itself and a few instances of vi.

Set the environment before.

And why not set it with QProcess?

[caduel]

In order to start vi you need a window (assuming you don't intend to simulate a user by writing to stdin).

So you will need to open some terminal application and run vi from there.

[auba]

And to start a graphical program like assistant? Is it possible to start it by commandline where the ".app/Contents/MacOS" part is some kind of autogenerated? I "only" have a new MacBook Pro, so I have no idea of the behaviour of the non-intel macs.

----

This means starting a shell, I have the same difficulties as on windows, but there startDetached is working. Well.

I found a swiss site with a small helper script.

Maybe I check the existence of ~/.term, generate it and make it executable... or I check it into the repository, because it belongs to the maker suite anyway...

thanks for that hint.

[auba]

Great. With the script I can start any bash command in a shell. Only when I close it, the window is left with "Prozess beendet". But I can live with it. Assistant and Designer are started with a symbolic QTDIR somewhere under "sources"... so everything runs now
[Solved]