On Fri, 14 Sep 2007, James Keenan via RT wrote:
> This thread and RT ticket (41168) have been under way since Jan 03 2007
> and I'm afraid that the discussion is collapsing under its own weight.
> May I make an attempt at summarizing the issues? Let's proceed from the
> outermost inwards.
[skipping to the relevant issue for this ticket]
> 3. Let's assume that we grant inter::progs more importance than other
> configuration steps. How should the absence of a working C-compiler be
> detected and reported?
Configure should try to compile and run a simple program. It should check
that the program ran, produced the desired output, and returned a
'success' exit status. If all those things don't check out, Configure
should present a message that tells the user precisely what was attempted
and what went wrong. Configure should probably offer to abort at that
point.
For comparison, here's what perl5's Configure does:
If the user specifies a non-existent C compiler (e.g. with
Configure -Dcc=NOcc) the following message is generated:
Configure: NOcc: not found
You need to find a working C compiler.
Either (purchase and) install the C compiler supplied by your OS vendor,
or for a free C compiler try http://gcc.gnu.org/
I cannot continue any further, aborting.
That's not too specific, but doesn't appear to cause too much confusion
either.
A more common occurrence (based on the mails I get) is to have a compiler,
but to have it not work as Configure expects for some reason or another.
After setting all the flags and libraries, Configure performs a sanity
check. It tries to compile and run a simple program. It checks both the
return value and the printed output. (Under at least one release of the
SFIO library, sfio's configuration script caused confusion between exit()
and _exit() with the net result that the program compiled fine, ran, and
exited with a return value of 0, but didn't actually print anything.
Accordingly, perl5's Configure tests both the output and the exit status.)
If this test fails, the following information is printed: (here I passed
in a bad library with sh Configure -Dlibs=-lnosuch
Checking your choice of C compiler and flags for coherency...
I've tried to compile and run the following simple program:
#include <stdio.h>
int main() { printf("Ok\n"); return(0); }
I used the command:
cc -o try -O -I/usr/local/include -L/usr/ccs/lib
-L/opt/SUNWspro/SC4.2/lib -L/usr/local/lib try.c -lnosuch
./try
and I got the following output:
ld: fatal: library -lnosuch: not found
ld: fatal: File processing errors. No output written to try
I can't compile the test program.
(The supplied flags or libraries might be incorrect.)
You have a BIG problem. Shall I abort Configure [y]
Ok. Stopping Configure.
This error message tells the user precisely what happened and gives enough
information for the user to easily reproduce (and, I hope, fix) the
problem.
--
Andy Dougherty [EMAIL PROTECTED]
