.left margin
.ifnot hlp
.subtitle
.HL 1 Section Headers
.endif hlp
.HELPC sections
.br

A section header consists of a section number of the form
n1.n2.n3...#followed by a section title.
If either the _.CHAPTER or _.APPENDIX command has been used, then
the current chapter or appendix number is attached to the front of
the section number, giving it the form n0.n1.n2.n3...
.ifnot small
The level of the section header is equal to the number of numbers in
the section header (not counting n0).  The exception is header level
1, which has the form n.0.
The _.STYLE HEADERS command can be used to override the default form
and print section numbers as a single number or letter, or with no number
at all.
The following commands control the header levels.
See also _.DISPLAY LEVELS, _.NUMBER LEVEL, _.ENABLE TRAILING ZERO and 
_.ENABLE LEVELS.
.if hlp
.if rsx.i5;ADDITIONAL HELP AVAILABLE: example LEVEL default SET STYLE INDENT
.endif rsx
.endif hlp
.HELPD example
.s.c;Examples
.s;Here is an example of the first header level:
.i5;1.0 The first header level!
.s;Here is an example of a header at level 4:
.br.i5; 1.2.3.4  Example of a header
.s;The following is a header at level 6:
.br.i5; 3.1.1.1.1.1  Example of a header
.s;The following is a header at level 3 in chapter number 7:
.i5;7.3.2.1
.HELPD LEVEL
.br
.endif small
.left margin +5
.q  _.HEADER LEVEL [+-n] [;][title]
.qq _.HL [+-n] [;][title]
.p.index  HEADER LEVEL  
starts a section with the specified section number and section title.
n can range from 1 to $LEVSIZ$. 
.ifnot small
Successive .HEADER LEVEL commands at the same level cause the section
numbers to increase sequentially.
If the document is chapter oriented, then n will be the chapter
number. Otherwise, it is the number of the _.HL 1 level. The _.HEADER LEVEL
command issues the commands: 
.nofill 
.skip 
.indent 5 
_.BREAK _.TEST PAGE 7 _.BLANK 2  
.skip 
.fill 
then prints the section number, two spaces, and the section name. If the level
number is preceded by +#or#-, the current level number is the previous one
+#or#- the value specified. 
.p;If the title is omitted, only the number is printed, and the next line of
text follows, separated by 2 spaces.  In this case, no distinction is
made between different level numbers.
.p; If the title is too long to fit on 1 line, it is filled, 
justified, and continued on the next line with indentation to line up with 
the first part of the title. 
Autohyphenation is not performed on header titles. 
.HELPD default
.s.c;DEFAULT
.s.lm +10 
.i-10;LEVEL 1 capitalizes the section title and skips a line.
.i-10;LEVEL 2 prints the section title (no caps) and skips a line.
.i-10;LEVELS 3,4,5 The title and the text following it are separated by
a dash.
.LM -10 
.s;These defaults can be changed by the _.STYLE HEADERS command.
.helpd SET
.iif FALL87 .bb
.q _.SET LEVEL +-n
.qq  _.SL +-n
.p.X SET> LEVEL
Sets the level for the next HEADER LEVEL command.
.iif fall87 .eb
.HELPD STYLE
.br
.endif small
.q _.STYLE HEADERS [n1],[n2],...[n9],[n10] 
.qq  _.STHL [n1],...[n10] 
.p.X STYLE> HEADERS 
changes the format used for various levels of section headers.
_.STYLE HEADERS also causes a line break.
.;This documentation change conforms to DSR
.iif SPR86 .bb
If a value is not supplied, the default is used.
.iif spr86 .eb
Default values are shown below in ().
.LM+5
.qq n1#=#Lowest level at which text starts on same line as title. (3) 
.qq n2#=#Lowest level with title capitalized. (1) 
.qq n3#=#Highest level with first letter of title in CAPS. ($LEVSIZ$) 
.qq n4#=#Lowest level with no level number. (7) 
.qq n5#=#Lowest level with centered title and number.  If the title and 
text are on the same line, no centering occurs. (7) 
.qq n6#=#Number of blank lines before the header. (2) 
.qq n7#=#Number of blank lines after the title. (1) 
.qq n8#=#Implicit test page value (7) 
.qq n9#=#Number of spaces between section number and title. (2) 
.qq n10=#Largest level printed as n.m.... ($LEVSIZ$)
.i5;(n10 not available in DSR)
.i5;DEFAULT: STYLE HEADERS 3,1,$LEVSIZ$,7,7,2,1,7,2,$LEVSIZ$
.ifnot small
.lm-5
.HELPD INDENT
.ENDIF SMALL
.q _.INDENT LEVELS n1,n2
.p.X INDENT LEVELS
causes the header levels to be indented by n1
from the left margin and n2 from the right margin.
.ifnot small
A positive value of n1 causes indentation to the right of the left margin.
A positive value of n2 causes indentation to the left of the right margin.
.i5;(Not available in DSR)
.endif small
.q _.INDENT LEVEL TITLES [n1],[n2]...[n$LEVSIZ$]
.p.x INDENT LEVEL TITLES
causes the section titles to be indented
from the normal level indention by an additional fixed amount.
.ifnot small
This can be used, for example, to line up all of the titles for level 1
independently of the titles for level 2.
If the spacing specified in the _.STYLE HEADERS
command is greater then the spacing specified by the _.INDENT LEVEL TITLES,
the style spacing is used.  When n is omitted the indentation is not altered.
.endif small
.i5;DEFAULT: _.INDENT LEVEL TITLES 0,0,0,0,0,0