Gnome GTK / Spawn CLI app - read output

Could someone point me to the source code or an example program that shows how to spawn a new application from gnome/gtk to a CLI application and read its output back into your gnome/gtk application?

Example:
GTK application calls "ls -a" and then the output of ls is shown in a GTK_ENTRY widget.

Thank you very much,

Matthew Ozor

I would do this by forking the command and writing it's output to a tmp file, then reading the tmp file into the entry.

Code:

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ls > tmp.txt

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I promise you will not find a way to feed a Command Line Interface application DIRECTLY into a gtk program, or for that matter any C program (or for that matter any program in any language).

Which also means you can't store the output in a string, etc. You have to use a text file.

Quote:

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I promise you will not find a way to feed a Command Line Interface application DIRECTLY into a gtk program, or for that matter any C program (or for that matter any program in any language).

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Umm . . . what about popen()?

(It lets you essentially start a new process and pipe that input into your program. I guess it technically uses a file stream as well, but without the hassle of a separate file.)

Umm . . . what about popen()?

Yes indeed! Well, I guess we are all living in a better universe for it anyway. This may be why they call me "the boy who..."

Besides popen(), there's of course the more powerful (but more tiresome) pipe/fork/exec dance.

Quote:

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Originally Posted by CornedBee

Besides popen(), there's of course the more powerful (but more tiresome) pipe/fork/exec dance.

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What I thought was the ONLY way, actually. So before I become a popen() convert, what does Corned Bee mean by "more powerful"?

popen() gives you a stream through which you can either read the child's stdout or write to its stdin. With the fork dance, you can pipe both input and output. For controlling an interactive shell process from within a GUI, this is actually essential.

Thank you very much for suggesting the popen() function as this is a nice clean way to add a external programs output to a gtk+ textview widget. I do intend to learn how to use pipes as this would give a real time output.

Here is a example code for that maybe helpful for people learning. It does require a pointer to a real textview1 widget to work.

Code:

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  FILE *fp;
 
  GtkTextBuffer *buffer;
  GtkTextIter  iter;

  buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (textview1));

  fp = popen("ls -a", "r");                       

  while ( fgets( line, sizeof line, fp))
  {
    gtk_text_buffer_get_end_iter (buffer, &iter);                       
    gtk_text_buffer_insert (buffer, &iter, line, -1);
  }

 pclose(fp);

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Thanks again,
Matthew Ozor