RE: [autoconf 2.49e] configure --help creates config.log

[Rainer Orth]

Tim Van Holder writes:

> > if run in the source directory as ./configure --help, but the source
> > directory should be considered as read-only.
> No it shouldn't; it's perfectly valid to configure & build in the source
> directory.  If you want to treat srcdir as read-only, you should be running

True, but this shouldn't hold for the purely informational ./configure
--help: I can see no use in creating config.log when there's no actual
configure run to diagnose.  Besides, this didn't happen in autoconf 2.13
(very likely intentionally) and thus should be considered a regression.

> configure from a different dir (../package/configure --help); and then
> config.log would be created there instead of srcdir.  Note that some rules

But this is awkward just to learn possible configure options.

> (automake's lex/yacc rules, for example), will still create things in the
> source directory (or try to anyway).

This shouldn't need to happen for a properly built distribution where
platform independent generated files are included in the distribution with
timestamps newer than their respective timestamps.  And even if the
distributions is improperly constructed, it's still controversial if
generated files should be created in $(srcdir) or in $(builddir).  Creating
those derived files may be necessary for the compilation to succeed, but
this is clearly not the case for configure --help: config.log has no use in
this case and is just a nuisance; I'm not even sure if <cmd> --help is
allowed to have side effects by the GNU coding standards.

        Rainer

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Rainer Orth, Faculty of Technology, Bielefeld University

Email: address@hidden