"Process failed to start: " and qprocess generic errors

[scott_hollen]

Afternoon --

I can't seem to find a simple problem I'm having addressed anywhere in the forum or google, so I'm hoping someone can point me in the right direction...I'm sure it's something small...

I am trying to call a simple cmd application that takes 2 parameters, an input file and output file with QProcess -- it looks like it should be a very easy thing to do but I'm getting errors that really don't help me much...if I use "proc->start(...)" the error I get is, "Process failed to start: ", and if I use proc->execute (...), I get "Unknown error"...It might be something in my pathnames, but I need another set of eyes at this point...

From the command line, this is how I call the application and it works perfectly:
C:\Users\Scott\Desktop\Star\Genriser\src\genriser test.input test.output

mainwindow.h

.
.
.
private:
   Ui::MainWindow *ui;
   QProcess *genriser_proc;

.
.
.
private:
   Ui::MainWindow *ui;
   QProcess *genriser_proc;

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mainwindow.cpp

QString genriser_dir;
QStringList arguments;
 
genriser_proc = new QProcess;
 
genriser_dir = "C:\\Users\\Scott\\Desktop\\Star\\Genriser\\src";
QDir::setCurrent(genriser_dir);
 
arguments << "test.input"; 
arguments << "test.output"; 
 
genriser_proc->start(program, arguments);

QString genriser_dir;
QStringList arguments;

genriser_proc = new QProcess;

genriser_dir = "C:\\Users\\Scott\\Desktop\\Star\\Genriser\\src";
QDir::setCurrent(genriser_dir);

arguments << "test.input"; 
arguments << "test.output"; 

genriser_proc->start(program, arguments);

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I have tried not setting a working directory and putting the full pathname of the executable and the files in the string, I've tried the overloaded versions of QProcess::start and execute, but to no avail.


Any ideas? I'm sure it'll be something embarrassing...

scott

[norobro]

Have you tried:

genriser_dir = "C:\\Users\\Scott\\Desktop\\Star\\Genriser\\src";
//QDir::setCurrent(genriser_dir);
genriser_proc->setWorkingDirectory(genriser_dir);

genriser_dir = "C:\\Users\\Scott\\Desktop\\Star\\Genriser\\src";
//QDir::setCurrent(genriser_dir);
genriser_proc->setWorkingDirectory(genriser_dir);

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[scott_hollen]

That's actually what I tried first but was getting a can't find directory or file error, so searching found me this:

http://www.qtforum.org/article/15350...y-problem.html

[ChrisW67]

Where is 'program' set and what is its value?

[scott_hollen]

Oops, that would help to have shown the whole piece of code -- cut and paste issues...

mainwindow.cpp

QString input_file;
   QString output_file;
   QString program;
   QString genriser_dir;
   QStringList arguments;
 
   input_file = "C:\\Users\\Scott\\Desktop\\Starmark\\Genriser\\src\\test.input";
   output_file = "C:\\Users\\Scott\\Desktop\\Starmark\\Genriser\\src\\test.output";
   program = "C:\\Users\\Scott\\Desktop\\Starmark\\Genriser\\src\\genriser";
   genriser_dir = "C:\\Users\\Scott\\Desktop\\Starmark\\Genriser\\src";
 
   genriser_proc = new QProcess;
 
   QDir::setCurrent(genriser_dir);
 
   arguments << input_file;
   arguments << output_output;
 
   genriser_proc->start(program, arguments);

QString input_file;
   QString output_file;
   QString program;
   QString genriser_dir;
   QStringList arguments;

   input_file = "C:\\Users\\Scott\\Desktop\\Starmark\\Genriser\\src\\test.input";
   output_file = "C:\\Users\\Scott\\Desktop\\Starmark\\Genriser\\src\\test.output";
   program = "C:\\Users\\Scott\\Desktop\\Starmark\\Genriser\\src\\genriser";
   genriser_dir = "C:\\Users\\Scott\\Desktop\\Starmark\\Genriser\\src";
 
   genriser_proc = new QProcess;
     
   QDir::setCurrent(genriser_dir);
     
   arguments << input_file;
   arguments << output_output;
     
   genriser_proc->start(program, arguments);

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If I fully qualify the pathnames in my variables, I get the "Process failed to start" error...However, if I remove the pathnames and just rely on the setCurrent command to define the directory, I get "Process crashed"...

When I did a qDebug() on "arguments", it shows the string encased in parentheses, and I'm wondering if that's where my problem is originating because my command line needs to look like this, "...\src\genriser test.input test.output"...Does the QStringlist append parenthesis or is that something that's just appearing with the debug?

I've also tried, "genriser_proc->start("genriser test.input test.output)" and that didn't work either...


scott


ed. calling my main application, which has no parameters, works -- so does run qtcreator if I point all my variables to it's directory, so that narrows it down to something to do with the arguments...

[scott_hollen]

I'm about to throw my Mac against the wall...Every application I invoke with QProcess works except for the one I need to have work...I even modified the external app to not need parameters but it still bombs...Running that app from the cmd line works; double clicking on it in File Manager works...Calling it from my Qt app generates a "Process crashed" error and I'm at a loss as to how to debug that...I didn't want to have to fold this app into my Qt app, but I'm almost to the point of having to do that...

scott

[ChrisW67]

If it is complaining that the process crashed then it must have found the file.

Are you sure the genriser program runs on its own without crashing?
Can you start a non-Qt command prompt (whatever it's called on a Mac), cd to the directory, and run the command yourself?
Is the environment that your sub-process inherits correct? Can the program find all its dynamically loaded dependencies (Qt libs etc.)?

When you say a "simple cmd application" do mean a simple executable or a shell script?