src/interfaces/libpq/fe-connect.c:7247-7254
Returns the client-side character encoding identifier for a PostgreSQL connection.
int
PQclientEncoding(const PGconn *conn)The PQclientEncoding function retrieves the current client-side character encoding setting for a PostgreSQL connection. Character encoding determines how text data is represented and interpreted between the client application and the PostgreSQL server. This function returns an integer identifier that corresponds to a specific character encoding (such as UTF-8, Latin-1, etc.).
The function first validates that the connection is not null and that the connection status is CONNECTION_OK, ensuring that encoding information is only retrieved from properly established connections. If these conditions are not met, the function returns -1 to indicate an error or unavailable encoding information.
*conn: Pointer to the PGconn connection object from which to retrieve the client encoding. Must be a valid, established connection.
- Functions called/Symbols referenced:
- CONNECTION_OK (connection status constant)
- Called from (representative examples):
- setup_connection (pg_dump.c)
- exec_command_encoding (psql command.c)
- SyncVariables (psql command.c)
- SendQuery (psql common.c)
- appendStringLiteralConn (string_utils.c)
- Various database utility commands (createdb, dropdb, vacuumdb, etc.)
- Returns int encoding identifier, or -1 if connection is invalid or not established
- This function is extensively used throughout PostgreSQL client tools for proper text handling and display
- The encoding affects how string literals, identifiers, and query results are processed and displayed
- Used by psql for proper character display and by dump utilities for correct data export
- Part of the core libpq interface for character encoding management
- The actual encoding names can be retrieved using pg_encoding_to_char() with the returned identifier
int PQclientEncoding(const PGconn *conn) {
// Return -1 if no connection or connection not properly established
if (!conn || conn->status != CONNECTION_OK)
return -1;
// Return the client encoding identifier
return conn->client_encoding;
}