Intel XENIX 286 Programmers Guide (86) - Tenox.tc

m4: Macro Processor XENIX Programming
The built-in macro dnl deletes all characters that follow it up to and including the next
newline. It is useful mainly for deleting empty lines that otherwise tend to clutter up
m4 output. For example, if you specify
define(N, 1 00)
define(M, 200)
define(L, 300)
the newline at the end of each line is not part of the definition, so it is copied into the
output, where it may not be wanted. If you add dnl to each of these lines, the newlines
will disappear.
Another way to achieve this is
divert(-1)
divert
Printing
define( ... )
The built-in macro errprint writes its argu ments out on the standard error file. Thus,
you can write
errpri nt('fatal error')
The built-in macro dumpdef is a debugging aid that dumps the current definitions of
defined terms. If there are no arguments, all definitions are output. Otherwise, only
the definitions of the terms given as arguments to dumpdef are output. The arguments
to dumpdef should be quoted.
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