preference range

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I did look at that function, but it didn't look right with the range_t parameter. I could not see how multiple values could define a range coupled with the max_value!

My variable is in my decoder, Wireshark will not use this variable. I only want to user to set a single number in the GUI, not a range. I would like the GUI to enforce an upper limit (i.e. 0-100). I don't see prefs_register_range_preference() as what I need.

OK, but making use of a range preference doesn't mean that you can only specify a range; you can specify a single number. I'm not saying this is ideal, but it might be better than what you have now, because you can at least enforce an upper limit.

it seems that "80,-1" is also allowed and worse, there's no indication given to indicate that it's invalid.

It is valid - it's a list of subranges, the first of which contains only 80 (80-80), and the second of which starts with the beginning value and runs up to 1 ({min}-1). (Yes, that's surprising, but it's valid - that's how the range syntax works. It uses - as an indication of a subrange, and allows subranges without a start or end.)

If you click OK now, the next time you look at the preference, it is changed to "80,1"

80-80 is the same as 80 and, if {min} is 1, that makes {min}-1 be 1-1, which is the same as 1.

OK, so I've added changed some uses of strtoul() to use ws_basestrtou32() in the preferences and range code, which means that, at least from the CLI, negative numbers are rejected for unsigned-integer preferences.

For the GUI, there are a number of things we can do, including either using validators for integral preferences, as I suggested for range preferences, or using spin boxes for integral preferences.