DB_ENV->log_printf()
#include <db.h>
int
DB_ENV->log_printf(DB_ENV *env, DB_TXN *txnid, const char *fmt, ...); The DB_ENV->log_printf() method appends an informational message to the Berkeley DB database environment log files.
The DB_ENV->log_printf() method allows applications to include information in the database environment log files, for later review using the db_printlog utility. This method is intended for debugging and performance tuning.
The DB_ENV->log_printf() method returns a non-zero error value on failure and 0 on success.
Parameters
txnid
If the logged message refers to an application-specified transaction, the txnid parameter is a transaction handle returned from DB_ENV->txn_begin(); otherwise NULL.
fmt
A format string that specifies how subsequent arguments (or arguments accessed via the variable-length argument facilities of stdarg(3)) are converted for output. The format string may contain any formatting directives supported by the underlying C library vsnprintf(3) function.
Errors
The DB_ENV->log_printf() method may fail and return one of the following non-zero errors:
EINVAL
An invalid flag value or parameter was specified.