read stdout with QProcess under Windows

[jlbrd]

Hi,
In QIde I use ctags to populate a combo with methods of a file. I use an option of ctags "-f-" who write the result of the parsing to stdout. Then I read stdout to parse the result. The code work fine under Linux. Under Windows nothing is read and lu.isEmpty() return true. ctags is a solid tool and I requests what does not work under Windows.

QProcess *testCtags = new QProcess();
testCtags->start("ctags", QStringList()<<"-f-" << "--fields=+S+K+n" << filename());
testCtags->waitForFinished(5000);
QString lu = testCtags->readAll();
if( !lu.isEmpty() )
{
	foreach(QString s, lu.split("\n") )
	{
		...
	}
}

QProcess *testCtags = new QProcess();
testCtags->start("ctags", QStringList()<<"-f-" << "--fields=+S+K+n" << filename());
testCtags->waitForFinished(5000);
QString lu = testCtags->readAll();
if( !lu.isEmpty() )
{
	foreach(QString s, lu.split("\n") )
	{
		...
	}
}

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Note : If I use connect for readyReadStandardError or readyReadStandardOutput signals the slot is never called.
Thanks

[nouknouk]

Hi Jean Luc,

maybe you should test the return value of waitForFinished() and just before test the return value of waitForStarted(). If one of them returns false it may be useful for better understanding the issue.

[jlbrd]

I think not because if I connect readyReadStandardError or readyReadStandardOutput to a slot, this slot it's never called. If I use connect I don't delete the process by delete. Thus not problem of waiting. But never works!

testCtags = new QProcess();
connect(testCtags, SIGNAL(readyReadStandardError()), this, SLOT(slotLoadCtags()) );
connect(testCtags, SIGNAL(readyReadStandardOutput()), this, SLOT(slotLoadCtags()) );
testCtags->start("ctags", QStringList()<<"-f-" << "--fields=+S+K+n" << filename());
...
//
void Editor::slotLoadCtags()
{
		QString lu = testCtags->readAllStandardOutput();
...
		testCtags->deleteLater();
...

testCtags = new QProcess();
connect(testCtags, SIGNAL(readyReadStandardError()), this, SLOT(slotLoadCtags()) );
connect(testCtags, SIGNAL(readyReadStandardOutput()), this, SLOT(slotLoadCtags()) );
testCtags->start("ctags", QStringList()<<"-f-" << "--fields=+S+K+n" << filename());
...
//
void Editor::slotLoadCtags()
{
		QString lu = testCtags->readAllStandardOutput();
...
		testCtags->deleteLater();
...

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[jlbrd]

Well, I created this program who wrote to stdout on Windows:

#include <stdio.h>
int main(int argc, char *argv[])
{
        fprintf(stdout, "Test line\n");
        fflush( stdout );
}

#include <stdio.h>
int main(int argc, char *argv[])
{
        fprintf(stdout, "Test line\n");
        fflush( stdout );
}

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then I replaced ctags by stdout.exe in QProcess::start and... It's work. Thus it's ctags who don't works and not QProcess.
End of my requests for QProcess. Now it is necessary to make work ctags!
thanks

[jlbrd]

In fact and after have finding, ctags works well with "-f-" to write to stdout. It's not my day, it's all!