MySQL 8.0 Release Notes
MySQL 8.0 Source Code Documentation
Many of the clients in MySQL source distributions are written in
C, such as mysql,
mysqladmin, and mysqlshow.
If you are looking for examples that demonstrate how to use the C
API, take a look at these clients: Obtain a source distribution
and look in its client directory. See
Section 2.1.2, “How to Get MySQL”.