The mtaLogv() routine is provided for programs that either need to provide a diagnostic interface accepting a va_list() argument, or want to provide some generalization of mtaLog(). Use of mtaLogv() ensures that diagnostic output is directed to the same output stream as other diagnostic information generated by the MTA SDK.
With one exception, consider a call to mtaLogv() as being identical to calling the C run-time library routine vprintf(). The call arguments for the two routines are identical including the formatting argument, fmt. The single exception is that, unlike vprintf(), a call to mtaLogv() always produces a single line of output to the channel’s log file. Consequently, do not attempt to write either partial or multiple lines with a single call to mtaLogv().
Do not include a terminating line feed or other record terminator in the output. That is, do not put a \n at the end of the formatting string.