The Vermont Views package consists of two sets of libraries, the development libraries and the production libraries. The main difference in the libraries is the type of errors that the functions detect.
Errors detected by the Vermont Views functions fall into two categories: development errors and runtime errors. Development errors are errors that can happen when writing a program. These types of errors include passing invalid parameters to a function, memory corruption, and undefined structures. Runtime errors are errors that can occur while a program is in use and tell of external conditions that prevent the program from continuing. In general, the only runtime errors are caused by insufficient memory and errors in opening or closing a file.
In the development libraries, both development and runtime errors are detected. In the production libraries, only runtime errors are detected.
When a function detects any error, the global error code VV_ERR is set. Functions that detect runtime errors additionally make an error return. For instance, when the function wn_def() cannot allocate memory for a window structure, the routine sets VV_ERR to MEMLACK and returns a NULLP.
