add text to entry fails. g_snprintf bad?

[edward hage <edha xs4all nl>]

I want to fill in an entry text with a double value from an variable named som.stepsize,
for example this value is som.stepsize = 0,001 and is defined as global so always available.

To add text I need a string so I use g_snprintf to create this string and then add it to 
the entry.

All kind of straightforward, but I have real big difficulties getting it right. I keep 
getting Segmentation errors.

Oh, I also tried sprintf (from stdio.h), but this did not help. Also tried g_strdup_printf 
   but then I got more problems with not being UTF-8 text, so I got strange ASCII-letters.

I think it must be some combination that gives the error, because when I g_print("%f 
\n",labeltext1) after the g_snprintf this gives the correct value (before Segmentation 
error occurs). But when I delete g_snprintf then the problem is solved ?

Also it seems that compiling sometimes does function, and not a next time, or am I getting 
paranoid over this. It has been bothering me for all day and evening.
By the way, I am using gtk+-2.0.



g_snprintf(labeltext1, 6, "%f", sim.stepsize);

void Create_tab_sim (GtkWidget *tabnumber)

   GtkWidget *stepsz;
   gchar *labeltext1;

// defined table and other widgets here, cropped it

   stepsz = gtk_entry_new ();
   gtk_table_attach_defaults (GTK_TABLE (table), stepsz, 1, 2, 0, 1);
   g_signal_connect (GTK_OBJECT(stepsz), "activate", (GCallback) simulation_event, 
GINT_TO_POINTER (STEPSIZE));

   gtk_entry_set_max_length ((GtkEntry *)stepsz, 6);
   g_snprintf(labeltext1, 6, "%f", sim.stepsize);  <----------
   gtk_entry_set_text (( GtkEntry *)stepsz, labeltext1); <----------

   // more data here , cropped it
   g_free(labeltext1);
}