m4: Errprint
1
1 14.1 Printing error messages
1 ============================
1
1 You can print error messages using 'errprint':
1
1 -- Builtin: errprint (MESSAGE, ...)
1 Prints MESSAGE and the rest of the arguments to standard error,
1 separated by spaces. Standard error is used, regardless of the
1 '--debugfile' option (⇒Invoking m4 Debugging options.).
1
1 The expansion of 'errprint' is void. The macro 'errprint' is
1 recognized only with parameters.
1
1 errprint(`Invalid arguments to forloop
1 ')
1 error->Invalid arguments to forloop
1 =>
1 errprint(`1')errprint(`2',`3
1 ')
1 error->12 3
1 =>
1
1 A trailing newline is _not_ printed automatically, so it should be
1 supplied as part of the argument, as in the example. Unfortunately, the
1 exact output of 'errprint' is not very portable to other 'm4'
1 implementations: POSIX requires that all arguments be printed, but some
1 implementations of 'm4' only print the first. Furthermore, some BSD
1 implementations always append a newline for each 'errprint' call,
1 regardless of whether the last argument already had one, and POSIX is
1 silent on whether this is acceptable.
1