These functions control miscellaneous details of libpq's behavior.
PQclientEncoding
Returns the client encoding.
int PQclientEncoding(const PGconn *conn
);
Note that it returns the encoding ID, not a symbolic string such as EUC_JP
. If unsuccessful, it returns -1. To convert an encoding ID to an encoding name, you can use:
char *pg_encoding_to_char(int encoding_id
);
PQsetClientEncoding
Sets the client encoding.
int PQsetClientEncoding(PGconn *conn
, const char *encoding
);
conn
is a connection to the server, and encoding
is the encoding you want to use. If the function successfully sets the encoding, it returns 0, otherwise -1. The current encoding for this connection can be determined by using PQclientEncoding
.
PQsetErrorVerbosity
Determines the verbosity of messages returned by PQerrorMessage
and PQresultErrorMessage
.
typedef enum { PQERRORS_TERSE, PQERRORS_DEFAULT, PQERRORS_VERBOSE, PQERRORS_SQLSTATE } 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 might span multiple lines). The VERBOSE mode includes all available fields. The SQLSTATE mode includes only the error severity and the SQLSTATE
error code, if one is available (if not, the output is like TERSE mode).
Changing the verbosity setting does not affect the messages available from already-existing PGresult
objects, only subsequently-created ones. (But see PQresultVerboseErrorMessage
if you want to print a previous error with a different verbosity.)
PQsetErrorContextVisibility
Determines the handling of CONTEXT
fields in messages returned by PQerrorMessage
and PQresultErrorMessage
.
typedef enum { PQSHOW_CONTEXT_NEVER, PQSHOW_CONTEXT_ERRORS, PQSHOW_CONTEXT_ALWAYS } PGContextVisibility; PGContextVisibility PQsetErrorContextVisibility(PGconn *conn, PGContextVisibility show_context);
PQsetErrorContextVisibility
sets the context display mode, returning the connection's previous setting. This mode controls whether the CONTEXT
field is included in messages. The NEVER mode never includes CONTEXT
, while ALWAYS always includes it if available. In ERRORS mode (the default), CONTEXT
fields are included only in error messages, not in notices and warnings. (However, if the verbosity setting is TERSE or SQLSTATE, CONTEXT
fields are omitted regardless of the context display mode.)
Changing this mode does not affect the messages available from already-existing PGresult
objects, only subsequently-created ones. (But see PQresultVerboseErrorMessage
if you want to print a previous error with a different display mode.)
PQtrace
Enables tracing of the client/server communication to a debugging file stream.
void PQtrace(PGconn *conn, FILE *stream);
On Windows, if the libpq library and an application are compiled with different flags, this function call will crash the application because the internal representation of the FILE
pointers differ. Specifically, multithreaded/single-threaded, release/debug, and static/dynamic flags should be the same for the library and all applications using that library.
PQuntrace
Disables tracing started by PQtrace
.
void PQuntrace(PGconn *conn);
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