PostgreSQL supports automatic character set conversion between
server and client for certain character sets.
pg_client_encoding() returns the client
encoding as a string. The returned string will be one of the
standard PostgreSQL encoding identifiers.
Note:
If libpq is compiled without multibyte encoding support,
pg_client_encoding() always returns
SQL_ASCII. Supported encoding depends on PostgreSQL
version. Refer to the PostgreSQL Documentation supported encodings.
The function used to be called pg_clientencoding().