27.8. Control Functions

These functions control miscellaneous details of libpq's behavior.


Determines the verbosity of messages returned by PQerrorMessage and PQresultErrorMessage.

typedef enum {
} PGVerbosity;

PGVerbosity PQsetErrorVerbosity(PGconn *conn, PGVerbosity verbosity);

PQsetErrorVerbosity sets the verbosity mode, returning the connection's previous setting. In terse mode, returned messages include severity, primary text, and position only; this will normally fit on a single line. The default mode produces messages that include the above plus any detail, hint, or context fields (these may span multiple lines). The VERBOSE mode includes all available fields. Changing the verbosity does not affect the messages available from already-existing PGresult objects, only subsequently-created ones.


Enables tracing of the client/server communication to a debugging file stream.

void PQtrace(PGconn *conn, FILE *stream);


Disables tracing started by PQtrace.

void PQuntrace(PGconn *conn);