Autocommit with Postgres 10

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Page: https://www.postgresql.org/docs/10/static/ecpg-sql-set-autocommit.html
Description:

Hi,

I am currently using PG10, and link my C program to the libpq.5.10.so file
for client feature usage.

I get the following error after trying to set auto commit (as I did before)
:

2018-05-03 11:16:50.253 CEST [50141] ERROR: unrecognized configuration
parameter "autocommit"
2018-05-03 11:16:50.253 CEST [50141] STATEMENT: SET AUTOCOMMIT TO ON

Could you tell me how to set autocommit to ON with PG 10 client library ?

Thank you