GTK get slider value - gtk

Question

How to get slider value in GTK?
#include <gtk/gtk.h>
#include <stdio.h>
#include <string.h>
GtkWidget *speed_sld,*speed_label;
static void transmit (GtkWidget *widget,gint *data)
{
float val = gtk_scale_get_digits(data);
g_print("Val is %f \n",val);
}
int main (int argc, char *argv[])
{
GtkBuilder *builder;
GtkWidget *window;
gtk_init (&argc, &argv);
builder = gtk_builder_new ();
gtk_builder_add_from_file (builder, "./ECU.glade", NULL);
window = GTK_WIDGET (gtk_builder_get_object (builder, "window1"));
//g_signal_connect (window, "destroy", G_CALLBACK (on_window_destroy), NULL);
speed_sld = GTK_WIDGET (gtk_builder_get_object (builder, "scale1"));
speed_label = GTK_WIDGET (gtk_builder_get_object (builder, "label1"));
g_signal_connect (speed_sld, "value-changed", G_CALLBACK (transmit), NULL);
gtk_widget_show_all (window);
gtk_main ();
}
How can i print slider value in transmit function?I tried printing data,*data etc how can i get the values inside function

Answer 1

data is a pointer to whatever data was provided in g_signal_connect (you provided NULL), so that doesn't make sense.
I'm guessing you got confused by looking at GtkScale documentation: remember that you also need to look at the parent widgets API, in this case GtkRange. This should work:
static void transmit (GtkRange *range, gpointer data)
{
g_print ("current value is %f\n", gtk_range_get_value (range));
}