# Allowing integers to overflow to 0
**URL:** https://discourse.julialang.org/t/allowing-integers-to-overflow-to-0/17394
**Category:** General Usage
**Tags:** integer-overflow
**Created:** [November 10, 2018, 8:58pm UTC](https://discourse.julialang.org/t/allowing-integers-to-overflow-to-0/17394 "2018-11-10T20:58:54Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@wherrera](https://discourse.julialang.org/u/wherrera)
#### Post date: [November 10, 2018, 8:58pm UTC](https://discourse.julialang.org/t/allowing-integers-to-overflow-to-0/17394/1 "2018-11-10T20:58:54Z")
I’ve come across a place where allowing a UInt8 to overflow to 0 on adding 1 is the proper behavior.
Is there something like a decorator macro to allow the overflow and not get the overflow error with adding 1 to 255::UInt8 ?
---
### Author:  [@favba](https://discourse.julialang.org/u/favba)
#### Post date: [November 10, 2018, 9:03pm UTC](https://discourse.julialang.org/t/allowing-integers-to-overflow-to-0/17394/2 "2018-11-10T21:03:59Z")
Julia doesn’t trow overflow errors by default:
```julia
julia> UInt8(255) + UInt8(1)
0x00
```
---
### Author:  [@yuyichao](https://discourse.julialang.org/u/yuyichao)
#### Post date: [November 10, 2018, 10:33pm UTC](https://discourse.julialang.org/t/allowing-integers-to-overflow-to-0/17394/3 "2018-11-10T22:33:09Z")
I assume you were doing,
```julia
julia> UInt8(UInt8(255) + 1)
ERROR: InexactError: trunc(UInt8, 256)
Stacktrace:
[1] throw_inexacterror(::Symbol, ::Any, ::Int64) at ./boot.jl:567
[2] checked_trunc_uint at ./boot.jl:597 [inlined]
[3] toUInt8 at ./boot.jl:659 [inlined]
[4] UInt8(::Int64) at ./boot.jl:719
[5] top-level scope at none:0
```
(Or the equivalent with a typed variable/field array element). You can avoid the overflow check in the **conversion** ( **NOT** the add) by using `%` instead. i.e.
```julia
julia> (UInt8(255) + 1) % UInt8
0x00
```
which could be useful in other cases but the better way to deal with `+ 1` in particular would be to do what @favba posted, i.e. make sure both operand have the right type to begin with.
---
### Author:  [@wherrera](https://discourse.julialang.org/u/wherrera)
#### Post date: [November 11, 2018, 4:24am UTC](https://discourse.julialang.org/t/allowing-integers-to-overflow-to-0/17394/4 "2018-11-11T04:24:08Z")
Ah the bug was in adding one not adding UInt8(1).
I did not know you could do modulus with types. Thanks.