MYSQL_RES *mysql_list_dbs(MYSQL *mysql, const char *wild)
20.4.31.1  Description
Returns a result set consisting of database names on the server that match
the simple regular expression specified by the wild parameter.
wild may contain the wildcard characters `%' or `_', or may
be a NULL pointer to match all databases.  Calling
mysql_list_dbs() is similar to executing the query SHOW
databases [LIKE wild].
You must free the result set with mysql_free_result().
20.4.31.2  Return values
A MYSQL_RES result set for success.  NULL if an error occurred.
20.4.31.3  Errors
CR_COMMANDS_OUT_OF_SYNC
- 
Commands were executed in an improper order.
 CR_OUT_OF_MEMORY
- 
Out of memory.
 CR_SERVER_GONE_ERROR
- 
The MySQL server has gone away.
 CR_SERVER_LOST
- 
The connection to the server was lost during the query.
 CR_UNKNOWN_ERROR
- 
An unknown error occurred.