Where is the MySQL error log?

MySQL has four logs, which reside in the mysqld data directory. They are:

Log	Information
error log	Problems pertaining to running, stopping, and starting mysqld
general query log	Records established client connections and statements issued from clients
binary log	Records all statements that modify data or pertain to replication
slow query log	Records all queries that exceed the amount of time allotted by the long_ query_time parameter or did not use indexes.