GTK+ Forums

cnewbie · Familiar Face Joined: 12 Jan 2010 Posts: 7

This code example was a great help for exactly what I was trying to do myself.

However, I get the following warning when compiling it:

Code: (Plaintext)
1 2 3 4	example.c: In function ‘on_execute_button_clicked’: example.c:41: warning: format not a string literal and no format arguments

Line 41 being error->message; :

Code: (Plaintext)
1 2 3 4 5 6	dialog = gtk_message_dialog_new (NULL, GTK_DIALOG_DESTROY_WITH_PARENT, GTK_MESSAGE_ERROR, GTK_BUTTONS_OK, [color=red]error->message);[/color]

tadeboro · Posted: Wed Jan 13, 2010 12:33 pm Post subject: Re: Warning when compiling

Hello and welcome to the GTK+ forums.

cnewbie · Familiar Face Joined: 12 Jan 2010 Posts: 7

cnewbie · Familiar Face Joined: 12 Jan 2010 Posts: 7

Another question:

This works fine for me with commands like "ls -la", "df" etc. However, it doesn't work with f.ex. "ping localhost". Then the application just freezes. I take it things like ping need more complex handling to execute in this manner?

Also, if I type just "ping" on the command line, I feedback on how to use the command (because it misses an argument). Is this possible to get in the gui?

LGV · Posted: Fri Jan 15, 2010 11:14 pm Post subject:

1) You just have to convert "ping localhost" into a NULL-terminated string vector, like this:

Code: (C)
1 2 3 4 5 6	gchar* string_vector[3]; string_vector[0] = "ping"; string_vector[1] = "localhost"; string_vector[2] = NULL;

And pass that string as the "command_line" parameter to g_spawn_command_line_sync (reference). You can do that conversion with the g_shell_parse_argv function (reference).

2) Assuming that ping uses the standard error to output errors (wich it probably does), then yes, you can retrieve the error message trough the "standard_error" parameter of g_spawn_command_line_sync.

cnewbie · Familiar Face Joined: 12 Jan 2010 Posts: 7

Hm...

I have a text which I get from a textentry widget:

Code: (Plaintext)
1 2 3 4	const gchar *adr; adr = gtk_entry_get_text(GTK_ENTRY(widgets->adrentry));

Then I try to convert this for use is the string_vector:

Code: (Plaintext)
1 2 3 4 5 6	gint argc; gchar *argv = NULL; gchar padr; padr = g_shell_parse_argv(adr, &argc, &argv, NULL);

This gives no warnings.
But when I try inserting it into the string_vector:

Code: (Plaintext)
1 2 3 4 5 6	gchar *string_vector[3]; string_vector[0] = "ping"; string_vector[1] = padr; string_vector[2] = NULL;

This gives the warning

Code: (Plaintext)
1 2 3	warning: assignment makes pointer from integer without a cast

For the "string_vector[1] = padr;" line.

Now, I understand this ERROR sometimes, but often I'm confused.

tadeboro · Posted: Sat Jan 16, 2010 1:11 pm Post subject:

Hello.

g_shell_parse_argv() returns gboolean, not gchar *, which makes compiler unhappy.

Tadej

cnewbie · Familiar Face Joined: 12 Jan 2010 Posts: 7

Sorry, I don't get it.

- Do need to convert the text from the TextEntry before inserting it into the string_vector?
- Then, do I need to convert the string_vector before passing it to g_spawn_command_line_sync?

LGV · Posted: Sat Jan 16, 2010 6:01 pm Post subject:

I'm sorry, I did a mistake. g_spawn_command_line_sync doesn't take a string vector as parameter, it just takes a command line; the function does the conversion from command line to string vector for you. So, you just have to call it this way:

Code: (C)

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#include <stdio.h>
#include <stdlib.h>
#include <glib.h>

int main(int argc, char** argv)
{
gchar* std_out = NULL;
gchar* std_err = NULL;
gint exit_code;
GError* error = NULL;
gchar* command_line = "ping localhost";

/* If fails, output errors and exit */
if(!g_spawn_command_line_sync(command_line, &std_out, &std_err, &exit_code, &error))
{
if(error)
{
g_print("Error: %s\n\n", error->message);
g_error_free(error);
error = NULL;
getchar();
exit(EXIT_FAILURE);
}
}

if(std_out)
{
g_print("std_out: %s\n\n", std_out);
g_free(std_out);
std_out = NULL;
}

if(std_err)
{
g_print("std_err: %s\n\n", std_err);
g_free(std_err);
std_err = NULL;
}

getchar();
return EXIT_SUCCESS;
}

tadeboro · Posted: Sat Jan 16, 2010 7:03 pm Post subject:

Hello all.

Just one note. This code will not work with commands that do not terminate on their own. For example, "ping localhost" will never return from g_spawn_command_line_sync() function call and thus application will appear frozen. For commands that do not terminate or take longer time to finish, async version of spawning would be better choice.

Tadej

cnewbie · Familiar Face Joined: 12 Jan 2010 Posts: 7

Thanks. However, when using the above code, I experience the exact same thing as using the way described in the beginning of this thread: The application just hangs when activating the code that runs the command, and I have to force quit it.

EDIT: Ah. tadeboro pointed that out just as I was writing my last comment.

Asyncroneous spawning seems to be what I need. My point with trying to learning this is that I want to make an application for testing SMTP server for things like Auth,, Vrfy etc., for use with a mail scanning gateway. So I figured making a "graphical pinger" would get me started.

tadeboro · Posted: Sat Jan 16, 2010 7:50 pm Post subject:

Hello.

I wrote a blog post about spawning processes using glib. You may find some interesting pointers there.

Tadej

cnewbie · Familiar Face Joined: 12 Jan 2010 Posts: 7

Ah, thanks. There are several pointers there, several of which I'm sure will at least tech me _something_.