Calling autoconf in a spec.

[Ralf Corsepius]

On 07/04/2011 02:04 PM, Sam Varshavchik wrote:
> Ralf Corsepius writes:
>
>> On 07/04/2011 01:18 PM, Sam Varshavchik wrote:
>>
>> > Both gcc and binutils are extensively regression-tested. Stuff that was
>> > compiled years ago, still works.
>> To some extend, yes,
>>
>> Nevertheless we all are permanently fixing gcc/binutils-compatibilities,
>> aren't we?
>
> Right. But the same cannot be said for autotools. The macros change,
Very rarely

> and
> configure scripts are expected to be updated to reflect the changes.
To some extend agreed. There were few such changes, but there were much 
more which didn't.

>> > The same cannot be said of autotools.
>> Well, check the sources - autoconf+automake have similar testsuites.
>
> Perhaps, but they would not be testing that ten-year old code still gets
> processed, without warnings.
>
> I've got C++ code that's more than ten years old. Still builds just
> fine, without any diagnostics.
Then you're lucky - May-be your C++ code is recent enough?

So far, most pre-ISO-C++ code I have encountered, esp. when originating 
from non-gnu platforms has required major surgery ;)

Worse, "advanced c++ code" often even requires surgery between g++ 
releases (Much of my own works is based on C++) ;)

> Try feeding an average ten-year old configure.in script to autoconf, and
> see what happens.

With pre-autoconf-2.49: "Poof" in most cases.
As with most pre-iso/ANSI-C++ code ;)

With post-autoconf-2.49: "minor issues" in most cases.


>> It's the same problem as with binutils/gcc: languages change, standards
>> change, incompatibilities are being introduced deliberately, bugs find
>> their ways in, old features get abandoned/new ones introduced etc.
>>
>> The real difference between the autotools and gcc is: Many people are
>> permanently modernizing their c/c++-code, but are expecting modern
>> autotools to support the bugs/non-documented features the autotools did
>> 10-15 years ago.
>
> Not really. Like I said, I have lots of code that, so far, didn't need
> any modernizing.
As I wrote above - lucky you!

> But I do recall an update to autoconf, a few releases ago, that I had to
> respond to, with some fixes to my configure scripts.
Likely the autoconf-2.13->autoconf-2.49 change ca. 10 years ago - It was 
incompatible in many cases.

Most other upgrades since then (10 years ago!!!), had been fairly 
harmless - An aspect why "autoreconf"/"autoupdate" in recent enough 
autotools-based configuration at least "appears to work" in most cases.

Ralf