Programs that run in terminal-based systems must be able to run on many different types of terminals. To do this, Vermont Views uses a terminal capabilities file (termcap file, for short). A termcap file is a database file containing the commands that the program needs to "talk" to the terminal and use its unique capabilities. A termcap file contains a section listing all the commands for each type of terminal that the program can support.
The Vermont Views termcap file is called vvtermcap. It contains entries for the types of terminals most commonly in use under the UNIX and VMS operating systems.
Vermont Views does not interrogate the vvtermcap file when it needs to interact with a terminal. Rather, during initialization, vv_init() reads an environment variable (VVTERM or TERM) and transfers the commands for the current terminal from vvtermcap to global variables, called the terminal interface variables. These variables are declared in vv_main.h. The terminal interface variables are then used by Vermont Views to interact with the terminal and include the size of the terminal screen, key definitions, supported physical attributes, cursor control strings, and other command strings used by Vermont Views routines that interact with the terminal.
