If the screen has not been initialized, or the <EM>level</EM>
parameter is out of range, the function returns <STRONG>ERR</STRONG>. Oth-
erwise, it returns the previous level: <STRONG>0</STRONG>, <STRONG>1</STRONG> or <STRONG>2</STRONG>.
If the screen has not been initialized, or the <EM>level</EM>
parameter is out of range, the function returns <STRONG>ERR</STRONG>. Oth-
erwise, it returns the previous level: <STRONG>0</STRONG>, <STRONG>1</STRONG> or <STRONG>2</STRONG>.