/**
   * Format a message to the thread-safe ACE logging mechanism.  Valid
   * options (prefixed by '%', as in printf format strings) include:
   *  - 'A': print an ACE_timer_t value (which could be either double
   *         or ACE_UINT32.)
   *  - 'a': abort the program at this point abruptly.
   *  - 'c': print a character
   *  - 'C': print a character string
   *  - 'i', 'd': print a decimal number
   *  - 'I': indent according to nesting depth (obtained from
   *         ACE_Trace::get_nesting_indent()).
   *  - 'e', 'E', 'f', 'F', 'g', 'G': print a double
   *  - 'l': print line number where an error occurred.
   *  - 'M': print the name of the priority of the message.
   *  - 'm': return the message corresponding to errno value, e.g., as
   *         done by strerror()
   *  - 'N': print file name where the error occurred.
   *  - 'n': print the name of the program (or "<unknown>" if not set)
   *  - 'o': print as an octal number
   *  - 'P': print out the current process id
   *  - 'p': print out the appropriate errno message from sys_errlist,
   *         e.g., as done by perror()
   *  - 'Q': print out the uint64 number
   *  - 'q': print out the int64 number
   *  - '@': print a void* pointer (in hexadecimal)
   *  - 'r': call the function pointed to by the corresponding argument
   *  - 'R': print return status
   *  - 'S': print out the appropriate _sys_siglist entry corresponding
   *         to var-argument.
   *  - 's': print out a character string
   *  - 'T': print timestamp in hour:minute:sec:usec format.
   *  - 'D': print timestamp in month/day/year hour:minute:sec:usec format.
   *  - 't': print thread id (1 if single-threaded)
   *  - 'u': print as unsigned int
   *  - 'w': prints a wide character
   *  - 'W': print a wide character string
   *  - 'x': print as a hex number
   *  - 'X': print as a hex number
   *  - 'z': print an ACE_OS::WChar character
   *  - 'Z': print an ACE_OS::WChar character string
   *  - '%': print out a single percent sign, '%'
   */