Although most information for the Index is gathered automatically, in some situations it must be done by hand.
@_: Force index entry to be underlined
This command applies to the next identifier that appears after the
@_. The index entry for that identifier will be underlined.
(By convention, this means `defined' or `declared'.)
This command is usually issued automatically. For example, the index
entries for the variables i and j in the C statement
int i, j; will be underlined, since FWEAVE understands
enough of the syntax to know that variables are being defined. Macro
definitions (begun by
@D or @M) will also be underlined automatically.