functions draw a border around the edges of the current or specified window.
These functions do not advance the cursor position.
These functions do not perform special character processing.
These functions do not perform wrapping.
The arguments in the left-hand column of the following table contain
single-byte characters with renditions, which have the following uses in
drawing the border:
Corner of the first line and the starting column
Corner of the first line and the ending column
Corner of the last line and the starting column
Corner of the last line and the ending column
If the value of any argument in the left-hand column is 0,
then the default value in the right-hand column is used.
If the value of any argument in the left-hand column is a multi-column
character, the results are undefined.
Upon successful completion, these functions return OK.
Otherwise, they return ERR.
No errors are defined.
These functions are only guaranteed to operate reliably on character sets in
which each character fits into a single byte, whose attributes can be
expressed using only constants with the A_ prefix.
The Single UNIX Specification, Version 2; The Open Group.