SPI_commit, SPI_commit_and_chain — commit the current transaction
void SPI_commit(void)
void SPI_commit_and_chain(void)
   SPI_commit commits the current transaction.  It is
   approximately equivalent to running the SQL
   command COMMIT.  After the transaction is committed, a
   new transaction is automatically started using default transaction
   characteristics, so that the caller can continue using SPI facilities.
   If there is a failure during commit, the current transaction is instead
   rolled back and a new transaction is started, after which the error is
   thrown in the usual way.
  
   SPI_commit_and_chain is the same, but the new
   transaction is started with the same transaction
   characteristics as the just finished one, like with the SQL command
   COMMIT AND CHAIN.
  
   These functions can only be executed if the SPI connection has been set as
   nonatomic in the call to SPI_connect_ext.