Printing error messages
=======================
You can print error messages using `errprint':
errprint(MESSAGE, ...)
which simply prints MESSAGE and the rest of the arguments on the
standard error output.
The expansion of `errprint' is void.
errprint(`Illegal arguments to forloop
')
error-->Illegal arguments to forloop
=>
A trailing newline is _not_ printed automatically, so it must be
supplied as part of the argument, as in the example. (BSD flavored
`m4''s do append a trailing newline on each `errprint' call).
To make it possible to specify the location of the error, two
utility builtins exist:
__file__
__line__
which expands to the quoted name of the current input file, and the
current input line number in that file.
errprint(`m4:'__file__:__line__: `Input error
')
error-->m4:56.errprint:2: Input error
=>