-W@: Set module warning flag.

FWEAVE can check module names for the possible anomalous conditions of "never used" or "multiple uses." These correspond to a module warning level, as in the following numbered list:

1. Never used.
2. Multiple uses.

The module warning flag is the bitwise OR of the desired warning levels; warning messages are printed only when the relevant bits are turned on. By default, it is 1, so only messages about never-used modules are printed. The -W@flag overrides the default. For example, to get messages only about multiple uses, say -W@2; to get no messages, say -W@0. One can put such an option into the .fweb initialization file (see Initialization).

FWEAVE will always complain about module names that are never defined.