DDS internal messages (as opposed to the API messages conrolled through c_print.c) are controlled by various definitions from the "log:" dictionary. See Message Logging for more detail.
Files: hint.c - Cleanup dirty text for message printing hinttype.c - Reconstruct a type declaration for diagnostic message operator.c - Operator message, run time assistance for tape handling verbose.c - Verbose message, optionally printed warn.c - Warning message and optional abort error.c - Error message and optional abort debug.c - Debug message and optional abort abort.c - Abort process execution panic.c - Panic message and forced abort printstr.c - "C" print string for errors, warnings, etc binmessage.c - Print pending "bin" message and begin another ftnprt.f - Print one line, using Fortran write (Currently bypassed by both defining dds_print_lu=-1 and not defining DDS_ALLOW_FORTRAN_PRINT)