Allocates or initializes a MYSQL object suitable for mysql_real_connect(). If mysql is a NULL pointer, the function allocates, initializes, and returns a new object. Otherwise, the object is initialized and the address of the object is returned. If mysql_init() allocates a new object, it is freed when mysql_close() is called to close the connection.

In a nonmultithreaded environment, mysql_init() invokes mysql_library_init() automatically as necessary. However, mysql_library_init() is not thread-safe in a multithreaded environment, and thus neither is mysql_init(). Before calling mysql_init(), either call mysql_library_init() prior to spawning any threads, or use a mutex to protect the mysql_library_init() call. This should be done prior to any other client library call.

An initialized MYSQL* handler. NULL if there was insufficient memory to allocate a new object.

In case of insufficient memory, NULL is returned.