# Contributing

CVC4 is distributed under the terms of the modified BSD license (see
    [COPYING](https://github.com/CVC4/CVC4/blob/master/COPYING) file).  By
submitting a contribution you automatically accept the conditions described in
[COPYING](https://github.com/CVC4/CVC4/blob/master/COPYING).
Additionally, we ask you to certify that you have the right to submit such
contributions.  To manage this process we use a mechanism known as [Developer
Certificate of Origin](https://developercertificate.org), which can be
acknowledged by signing-off your commits with `git commit -s`.  We require all
pull requests to be squashed into a single commit and signed-off.

```
Developer Certificate of Origin
Version 1.1

Copyright (C) 2004, 2006 The Linux Foundation and its contributors.
1 Letterman Drive
Suite D4700
San Francisco, CA, 94129

Everyone is permitted to copy and distribute verbatim copies of this
license document, but changing it is not allowed.


Developer's Certificate of Origin 1.1

By making a contribution to this project, I certify that:

(a) The contribution was created in whole or in part by me and I
    have the right to submit it under the open source license
    indicated in the file; or

(b) The contribution is based upon previous work that, to the best
    of my knowledge, is covered under an appropriate open source
    license and I have the right under that license to submit that
    work with modifications, whether created in whole or in part
    by me, under the same open source license (unless I am
    permitted to submit under a different license), as indicated
    in the file; or

(c) The contribution was provided directly to me by some other
    person who certified (a), (b) or (c) and I have not modified
    it.

(d) I understand and agree that this project and the contribution
    are public and that a record of the contribution (including all
    personal information I submit with it, including my sign-off) is
    maintained indefinitely and may be redistributed consistent with
    this project or the open source license(s) involved.
```

If you are interested in becoming a long term contributor (for example, a new
decision procedure implementation) to the CVC4 project, please contact one of
the [project leaders](#project_leaders).  We'd be happy to point you to some
internal documentation to help you out.