Re: autoconf: undocumented limitation

[Bruno Haible]

Ralf Wildenhues wrote:
> Are you complaining that the limitation of 'awk' is not documented, or
> that the limitation of 'config.status' is not documented?

Actually, both. The limitation of 'awk' can be documented in section
"Limitations of Usual Tools", and the limitation about config.status
should be mentioned in the documentation of AC_CONFIG_FILES.

> If the 
> latter, then no, I don't think we should document that.  We should just
> document that config.status works only on text files, i.e., the line
> length is limited to LINE_MAX

Saying only "text files" would not be sufficient. The same long line
in a .m4 file is supported without problems; these are also text files.

Please say that the line length is limited. But what is LINE_MAX? If you
mean LINE_MAX from <limits.h> [1], then such a statement is useless,
because this value is platform dependent, and a reference to POSIX [2]
does not help because HP-UX 11.00 and IRIX 6.5 are far away from POSIX
compliance.

> Actually, we should fix config.status if somebody sees a portable way.
> sed only gets us to 4000 bytes which I don't think is worth the hassles
> of pre- and postprocessing the stuff we feed through awk; and sh read -r
> is not portable enough.

I agree that it's too much hassles. The limitation is harmless for files
that are written manually, but can hurt for generated files. The developers
of tools that generate such files (gnulib-tool, in this case, but also
automake) need to be able to know about this limitation.

Bruno


[1] http://www.opengroup.org/onlinepubs/009695399/basedefs/limits.h.html
[2] http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap01.html