I hereby release all content that I post, or have posted, to Stack Overflow into the public domain.
Content posted to Stack Overflow (questions and answers) are owned (in terms of copyright) by the original author and licensed perpetually to Stack Overflow, granting Stack Overflow permission to use, redistribute, and re-license that content as they wish.
https://stackoverflow.com/legal/terms-of-service#licensing
(See the section "Subscriber Content".)
Stack Overflow, in turn, licenses that content to the world under the CC-by-SA 3.0 license, with attribution required.
https://creativecommons.org/licenses/by-sa/3.0/
It is my personal opinion that Stack Overflow's definition of acceptable attribution is under-defined and excessively onerous.
Therefore, as the copyright owner of the content I have posted, I reserve the right to release my content under additional licenses, and I choose to release it under the public domain.
If you choose to use, modify, and/or redistribute content which I have authored on Stack Overflow, with or without attribution, you may do so under the freedoms defining public domain content, or (at your discretion) under the existing license offered by Stack Overflow.