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Old 02-09-2011, 04:38 PM   #1
axd
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Registered: Feb 2011
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interface not responding in glade 3 / gtk with C


Hi,

I am a fairly new ubuntu user. I am using ubuntu 10.04 and glade 3 for building a simple interface that uses C .

In my interface , I have created two buttons : start and stop .Tofocus on my actual problem , I have created a simpler UI and code .

start button runs a while(1) loop and stop should stop the loop .

The problem is , when I press start , the gui freezes and I cannot press any other button . I cant even close my app.After some thorough experimentation, I found out that when I press start , it never comes out of the while loop .

I need the loop to keep running until I press stop . What should i do ?

Here are the functions for the clickable buttons :

Code:
void
on_start_button_clicked (GtkButton *button, gpointer user_data)
{

	flag1=0;
	
	while(1)
	{

		printf("**********checking !!!! ********\n\n");
		
		if(flag1 == 1) 
				break;
	}
}


void
on_stop_button_clicked (GtkButton *button, gpointer user_data)
{
 
        flag1=1; 	

}
 
Old 02-10-2011, 09:32 AM   #2
schneidz
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Registered: May 2005
Location: boston, usa
Distribution: fc-15/ fc-20-live-usb/ aix
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^ i dont know about the freezing issue (try putting in something like sleep(1); after the pprintf()) but the flag1 variable is not global.
what that means is that on_start_button_clicked's flag1 is not the same as on_stop_button_clicked's flag1.
 
Old 02-10-2011, 10:02 AM   #3
axd
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Registered: Feb 2011
Posts: 2

Original Poster
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Quote:
Originally Posted by schneidz View Post
^ i dont know about the freezing issue (try putting in something like sleep(1); after the pprintf()) but the flag1 variable is not global.
what that means is that on_start_button_clicked's flag1 is not the same as on_stop_button_clicked's flag1.
Thanks for the reply schneidz .

The flag1 variable is in fact global . When i click stop before I click start , the loop runs once and exits (that would only happen if the value of flag1 changed to 1 before i pressed start).

I also tried putting sleep() , but the loop would only free up my gui on its exit condition being satisfied.

If I replace the while(1) with :

Code:
int c=0;

while(c<100)
{

  printf("*********checking!!!!*******");
  
  if(flag1==1) break;
  c++;

}

the app would still run through the whole while loop ... I cannot press any other button till then .
 
Old 02-10-2011, 01:09 PM   #4
schneidz
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Registered: May 2005
Location: boston, usa
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Quote:
Originally Posted by axd View Post
The flag1 variable is in fact global . When i click stop before I click start , the loop runs once and exits (that would only happen if the value of flag1 changed to 1 before i pressed start)...
i find it weird that on_start_button_clicked sets flag1=0 before the while loop so it should never break out of the while.

maybe stepping thru the program in gdb mite help ?

edit: i dont think it is good programming behaviour to use breaks;

maybe something like this would be better:
Code:
void on_start_button_clicked (GtkButton *button, gpointer user_data)
{
	bool flag1=0;
	while(flag1 == 0)
	{
		printf("**********checking !!!! ********flag1 = %b\n\n",flag1);
	}
}
is it possible on_start_button_clicked could return a pointer of a bool instead of a void ?

Last edited by schneidz; 02-10-2011 at 01:15 PM.
 
  


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