void (*db_errcall_fcn)(const char *errpfx, char *msg));
When an error occurs in the Berkeley DB library, a Berkeley DB error or an error
return value is returned by the function. In some cases, however,
the errno value may be insufficient to completely describe
the cause of the error, especially during initial application debugging.
The DB_ENV->set_errcall and DB->set_errcall methods are used to
enhance the mechanism for reporting error messages to the application.
In some cases, when an error occurs, Berkeley DB will call
db_errcall_fcn with additional error information. The function
must be declared with two arguments; the first will be the prefix string
(as previously set by DB->set_errpfx or DB_ENV->set_errpfx);
the second will be the error message string. It is up to the
db_errcall_fcn function to display the error message in an
Alternatively, you can use the DB->set_errfile or
DB_ENV->set_errfile methods to display the additional information via
a C library FILE *.
This error-logging enhancement does not slow performance or significantly
increase application size, and may be run during normal operation as well
as during application debugging.
The DB_ENV->set_errcall interface may be called at any time during the life of
Database Environments and Related Methods
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