Contents | < Browse | Browse >
Filling In Parameters
=====================

   Some terminal control strings require numeric "parameters".  For
example, when you move the cursor, you need to say what horizontal and
vertical positions to move it to.  The value of the terminal's `cm'
capability, which says how to move the cursor, cannot simply be a
string of characters; it must say how to express the cursor position
numbers and where to put them within the command.

   The specifications of termcap include conventions as to which
string-valued capabilities require parameters, how many parameters, and
what the parameters mean; for example, it defines the `cm' string to
take two parameters, the vertical and horizontal positions, with 0,0
being the upper left corner.  These conventions are described where the
individual commands are documented.

   Termcap also defines a language used within the capability
definition for specifying how and where to encode the parameters for
output.  This language uses character sequences starting with `%'.
(This is the same idea as `printf', but the details are different.)
The language for parameter encoding is described in this section.

   A program that is doing display output calls the functions `tparam'
or `tgoto' to encode parameters according to the specifications.  These
functions produce a string containing the actual commands to be output
(as well a padding spec which must be processed with `tputs'; 
Padding).

* Menu:

* Encode Parameters   The language for encoding parameters.
* Using Parameters   Outputting a string command with parameters.