How to use g_spawn_command_line_sync ?

gtk_chan · **Joined:** Mon Nov 10, 2008 6:54 am **Posts:** 64

I tried to create a simple IDE. Then when I tried to pass the command :

Code:

void compile_clicked( GtkWidget *w, TextEditor *editor )
{
    char          *output;
    GError       **error = NULL;
    GtkTextBuffer *buffer;
   
    string command_line =  "g++ main.cpp -o main";
   cout << command_line << endl;
   cin.ignore( 80, '\n' );

    g_spawn_command_line_sync( command_line.c_str(),
                               &output,
                               NULL,
                               NULL,
                               error );
   
    buffer = gtk_text_view_get_buffer( GTK_TEXT_VIEW( editor->error_textview ) );
    gtk_text_buffer_set_text( buffer, output, -1 );
}

It compiled fine, but after I click the compile_clicked button, my app was completely freeze :( ! I don't know why since which other command line such as "cat" or "find", it works really fine. Could anyone give me a hint where I did wrong ? Thanks in advance !

tadeboro · **Posted:** Fri Jul 03, 2009 7:08 am

Hello.

It's normal for application to "freeze" when using sync version of spawning. g++ will take some time to complete entire operation, and in the mean time, your application will be frozen.

To get the idea how long your app will be frozen, try executing your command on a command line and check how much time it takes to finish (my guess would be that g++ will take couple of seconds to finish).

If you would like to avoid being frozen, use async version of spawning and read output directly from pipe in idle or timeout handler.

gtk_chan · **Joined:** Mon Nov 10, 2008 6:54 am **Posts:** 64

Thanks tadeboro !

Quote:

Hello.
If you would like to avoid being frozen, use async version of spawning and read output directly from pipe in idle or timeout handler.

I'm not sure I get this point, can you give me a minimal example ?
And another question is :
With shell we have that :

Code:

g++ main.cpp -o main 1> output.txt 2> error.txt

where :
+ output.txt will hold the result of standard output.
+ error.txt will hold the result of standard error.
Is there any function in GTK+ or GLib could deal with standard error ?

tadeboro · **Posted:** Wed Jul 15, 2009 8:58 pm

Hi.

I wrote a quick introduction on spawning processes using glib's functions. Sample code also includes reading from stdout and stderr.

You can find it here: http://tadeboro.blogspot.com/2009/07/spawning-processes-using-glib.html

gtk_chan · **Joined:** Mon Nov 10, 2008 6:54 am **Posts:** 64

Great :D ! Thanks a lot tadeboro !

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