Normally, all foreign data access commands invoked by the NDF library execute silently, unless an error occurs or a command writes information to standard output (this should normally be avoided). To assist in debugging, however, the NDF library provides a tuning parameter `SHCVT'. This can be used to make it display all commands before they are executed but after message token substitution has taken place.
To enable this feature, the `SHCVT' tuning parameter should be set to 1. This can be done from within an application by calling the NDF_TUNE routine (see SUN/33), or from outside the application by setting the NDF_SHCVT environment variable, as follows:
setenv NDF_SHCVT 1
Adding Format Conversion Facilities to the NDF Data Access Library