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Trace Output

Initially trace output is written to STDERR. Both the $h->trace and DBI->trace methods take an optional $trace_filename parameter. If specified, and can be opened in append mode, then all trace output (currently including that from other handles) is redirected to that file. A warning is generated if the file can't be opened.

Further calls to trace() without a $trace_filename do not alter where the trace output is sent. If $trace_filename is undefined, then trace output is sent to STDERR and the previous trace file is closed.

Currently $trace_filename can't be a filehandle. But meanwhile you can use the special strings "STDERR" and "STDOUT" to select those filehandles.