+.SS Terminal Size
+.PP
+Besides the special commands (e.g., \fBclear\fP),
+@TPUT@ treats certain terminfo capabilities specially:
+\fBlines\fP and \fBcolumns\fP.
+@TPUT@ calls \fBsetupterm\fP(3X) to obtain the terminal size:
+.bP
+first, it gets the size from the terminal database
+(which generally is not provided for terminal emulators
+which do not have a fixed window size)
+.bP
+then it asks the operating system for the terminal's size
+(which generally works, unless connecting via a serial line which
+does not support \fINAWS\fP: negotiations about window size).
+.bP
+finally, it inspects the environment variables \fBLINES\fP and \fBCOLUMNS\fP
+which may override the terminal size.
+.PP
+If the \fB\-T\fP option is given
+@TPUT@ ignores the environment variables by calling \fBuse_tioctl(TRUE)\fP,
+relying upon the operating system (or finally, the terminal database).