The libecpg library primarily contains "hidden" functions that are used to implement the functionality expressed by the embedded SQL commands. But there are some functions that can usefully be called directly. Note that this makes your code unportable.
ECPGdebug(int on, FILE *stream) turns on debug logging if
called with the first argument non-zero. Debug logging is done on
stream. The log contains all
SQL statements with all the
input variables inserted, and the results from the PostgreSQL server. This can be very useful
when searching for errors in your SQL statements.
Note: On Windows, if the ecpg libraries 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.
ECPGget_PGconn(const char *connection_name) returns the library
database connection handle identified by the given name. If
connection_name is set to
NULL, the current connection handle is
returned. If no connection handle can be identified, the function
returns NULL. The returned connection
handle can be used to call any other functions from libpq, if necessary.
Note: It is a bad idea to manipulate database connection handles made from ecpg directly with libpq routines.
the current transaction status of the given connection identified
by connection_name. See Section 31.2 and libpq's
PQtransactionStatus() for details about the
returned status codes.
ECPGstatus(int lineno, const char* connection_name) returns true if you
are connected to a database and false if not. connection_name can be NULL if a single connection is being used.