Hi all,
I am giving a UI for a library which has been developed in core ANSI C.
The library calls a function close to 1000 times and is highly voluminous
in terms of space and time. I want to call this function 1000 times from
my UI.
I have made a dll file out of the C library, and I am using glade for GTK
front end. I have written ANSI C code snippets to check if the library
functions are working, and they appear to be working very well without any
problems.
While I told that this function call from the library takes a lot of time,
I have a progress bar in my UI, and while runnning this library function,
my progress bar keeps updating the fraction of work done by that
library[the fraction is actually computed by the C library function,
written into a file, and the timeout function keeps reading fraction value
from the same file periodically and updates its fraction].
For this I have written a time out function which keeps updating fraction
regularly in the progress bar.
So, I call this time out function first, and immediately I call this C
library function, and then followed by:
while (gtk_events_pending ())
{
g_print("[.]");
gtk_main_iteration ();
}
so that the timeout function doesnt have to blocked until this big
function is over, and it can keep updating fraction.
I am now facing really weird problems here.
1. My time out function is NOT BEING CALLED AT ALL. I am inserting a few
g_prints in the time out function, and I see nothing on the console.
Moreover, no updates are happening to progress bar fraction. Only after
fraction reaches 0.99, progress bar time out function is called.
2. My C library function crashes if I make changes to the timeout function
or the callback function. Windows is full of mysteries and I dont even
know why it crashed. When I include a g_print somewhere in the callback
function or timeout function, it starts working, and then suddenly stops
working
I am using windows MingGw-Msys-GTK2.0-glade combination for writing my
apps in windows.
Pseudo code for my call back function [for some button which will initiate
action] is as follows:
/***************CALL BACK FUNCTION CODE SNIPPET ***********************/
g_timeout_add(1500,progress_timeout,progressbarwidget);
f1();//THE BIG FUNCTION WHICH WILL RUN CLOSE TO A FEW HOURS
while (gtk_events_pending ())
{
g_print("[.]");
gtk_main_iteration ();
}//THIS SO THAT THE TIME OUT FUNCTION WILL BE ABLE TO CALL ITSELF
/****************END CALL BACK FUNCTION CODE SNIPPET**********************/
/****************TIME OUT FUNCTION *************************************/
static gboolean progress_timeout( gpointer pbar)
{
/*
1. Open file frac.v in read mode.
2. Read fraction.
3. Convert read fraction into double.
4. Update progress bar with fraction.
5. If fraction >=0.99, then deem that work is complete, so return true
to
g_timeout_add.
*/
FILE *fp;
gchar *buffer;
gdouble fraction = 0.0;
//1. Open file frac.v in read mode.
fp = fopen("frac.v","r");
if(fp==NULL)
{
displayError("Unable to update Progress bar.\n");
return FALSE;//Stop updating
}//End if fp==NULL
/*
Buffer will hold the fraction read from file. Fraction is of precision
5,
and will be between 0 and 1. So, size = 1[0//1]+1['.']+5[precision 5]
+1[EOS] = 8
*/
buffer = (gchar *)g_malloc0(8*sizeof(gchar));
//2. Read first line into buffer
fgets(buffer,8,fp);
fclose(fp);
//Buffer contains fraction.
//3. Convert read fraction into double[until end of buffer].
fraction = strtod(buffer,NULL);
//4. Update progress bar with fraction.
gtk_progress_bar_set_fraction (GTK_PROGRESS_BAR (pbar), fraction);
//Free memory
g_free(buffer);
//5. If fraction >=0.99, then deem that work is complete, so return true
to g_timeout_add.
if(fraction>=0.99)//If work is complete.
{
return FALSE;//Stop updating.
}
else//If work is not complete.
{
g_print("Time out function called");
return TRUE;
}
}//End function progress_timeout
/******************END TIME OUT FUNCTION *********************************/
1. Why should my C library function [which otherwise is doing very well]
crash just because I made some print changes in callback and time out ?
2. Since my timeout function has file I/O operations, is it that file I/Os
are still blocked even if I insert the gtk_main_iteration() call inside
while loop as I have indicated ?
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