QProcess

[jaca]

The code below in this SIGNAL clicked () a QPushButton. Every time I change the file mpl.tex I click the Button to update the file mpl.pdf, but this update only happens when click twice the Button. In the first click it shows the mpl.pdf old and the second click it updates.



QProcess *latexfile = new QProcess;
latexfile->start("latex", QStringList() << "mpl.tex");
QProcess *psfile = new QProcess;
psfile->start("dvips", QStringList() << "-ta4" << "-o" << "mpl.ps" << "mpl.dvi");
QProcess *pdffile = new QProcess;
pdffile->start("ps2pdf", QStringList() << "mpl.ps" << "mpl.pdf");
QProcess *openpdf = new QProcess;
openpdf->start("/usr/bin/acroread", QStringList() << "mpl.pdf");


Somebody has idea of as to make this?
Thanks.

[wysota]

QProcess works asynchronously, so if you want to start a chain of commands, you can't do it like this. You have to wait until one commands finishes its execution before starting the next.

[jaca]

I delete the files mpl.dvi, mpl.ps and mpl.pdf. Modify the file mpl.tex open the program click on Button, who has the code below, and it shows that the mpl.pdf delete previously. I do not understand. This file is updated only when mpl.pdf click for the second time the Button.


void Mpl::openPdf()
{
QProcess *latexfile = new QProcess;
QProcess *psfile = new QProcess;
QProcess *pdffile = new QProcess;
QProcess *openpdf = new QProcess;

latexfile->start("latex",QStringList() << "mpl.tex");
if (latexfile->waitForStarted())
cout << "Erro" << endl;
psfile->start("dvips", QStringList() << "-ta4" << "-o" << "mpl.ps" << "mpl.dvi");
pdffile->start("ps2pdf", QStringList() << "mpl.ps" << "mpl.pdf");
openpdf->start("/usr/bin/acroread", QStringList() << "mpl.pdf");
}

Somebody can help me, please?:confused:

[jaca]

QProcess works asynchronously, so if you want to start a chain of commands, you can't do it like this. You have to wait until one commands finishes its execution before starting the next.

Do not understand very well, I have to wait a while? How do this? How do I know whether the execution has ended?

[wysota]

Take a look at QProcess API and see what signals it emits. Also I suggest reading all its docs and taking a look at examples if there are any. Anyway in your case I'd suggest using system() instead of QProcess, at least for some of the calls.

[jaca]

Anyway in your case I'd suggest using system() instead of QProcess, at least for some of the calls.

Really I did. Thanks.