Re: [XForms] problem setting value of slider

[Jens Thoms Toerring]

Hi Jos,

On Wed, May 21, 2014 at 11:00:33PM +0200, jos wrote:
> I'm working on a program which has a few sliders.
> While setting min and max values of one of them, it crashes.
> In gdb this is (part of) the backtrace I see:
> 
> Program received signal SIGSEGV, Segmentation fault.
> fl_set_input (obj=0x0, str=0x8174518 "0") at input.c:1856
> 1856        FLI_INPUT_SPEC *sp = obj->spec;
> (gdb) bt
> #0  fl_set_input (obj=0x0, str=0x8174518 "0") at input.c:1856
> #1  0xb7eb58ea in fl_set_input_f (obj=0x0, fmt=<optimized out>) at
> input.c:1928
> #2  0xb7ed3647 in fl_set_spinner_value (obj=0x81670f8,
> val=219.98316955566406) at spinner.c:452
> 
> If I understand this correctly there is a spinner object 0x81670f8
> (line #2)
> which is going to be set with a value 219.9831...
> The call to fl_set_input however shows obj=0x0 (line #1)
> which looks to me like it has no object / the object is Null.
> Am I interpreting this correctly

Your analysis looks quite reasonable to me!

> and if so, is this happening inside the library (in input.c) or
> might this be caused by some error in my code?

Alas, that's a question I can't answer from the data I have.
It definitely could be a bug in the library but it could also
be the result of assigning to a stray pointer in your program.
During a short look at the spinner.c file I didn't find a
glaring mistake, but that doesn't prove anything. Would
you be prepared to send me the sources for the program in
which this happens, with some hints of how I can reproduce
the error? That would make it much easier to come up with
a good answer (and perhaps a bug fix to the library).

                       Best regards, Jens
-- 
  \   Jens Thoms Toerring  ________      address@hidden
   \_______________________________      http://toerring.de