Slightly misleading ./configure output (was: RE: Segfault when a gnuplot graph is closed?)

[Atwood, Robert C]

 I hope that this is helpful, it is certainly starting to teach me about
Configure scripts


Here is the message (found in ./configure)

  32873 if $risky_lesstif; then
  32874 echo
  32875 echo "configure: This $DDD release requires LessTif 0.87 or later."
  32876 echo "Upgrade to a recent LessTif version or continue at own risk."
  32877 fi

which appears to come from this part of configure.ac:

    992 dnl
    993 if $risky_lesstif; then
    994 echo
    995 echo "configure: This $DDD release requires LessTif 0.87 or later."
    996 echo "Upgrade to a recent LessTif version or continue at own risk."
    997 fi
    998 dnl

However, this message appeared when there was no version of LessTif at all
installed, OpenMotif installed but the openmotif-devel-*.rpm was not
installed. In fact, Xm.h was missing entirely. Yes I suppose that is pretty
dumb but I bet I am not the last person to do it. This message appeared
quite prominently at the very end of the configure process, leading me to
believe that LessTif was the only place that Xm.h could be obtained from.  

The message implies firstly that I really ought to install LessTif, and
secondly that I am able to continue. In fact I was not able to continue at
all because the files which include Xm.h would fail to complile. Now I have
learned that I do not need LessTif specifically, just that the OpenMotif
headers that were not installed. 

It could be improved by first somehow checking if there is any version of
LessTif at all, and checking whether the file Xm.h is present. Alternately,
it could be improved by changing the message to suggest the possibility that
Xm.h is not installed at all.

   997 echo "This message is also printed if the motif-compatible library
Xm.h is missing."

The relevant section for setting the value of $risky_lesstif from
configure.ac appers to be the section below. Without learning the configure
program details, it seems that it applies some sort of Boolean test on the
file Xm.h, if the test returns 0 (first option) the message is not
displayed, and if the test returns 1(second option_  the message is
displayed. It presumably returns 0 iff the lesstif version information in
the file matches the condition, otherwise it always returns 1, even if the
file does not exist. Apparently if the OpenMotif version of Xm.h is
installed, this test is bypassed entirely or returns 0 due to the 'ifdef
LESSTIF_VERSION' directive. If anohter variable such as $xmh_present could
be created with the result of testing for this file , an alternate message
could be printed if both are true.  
 

(configure.ac)
    1 $Id: configure.ac,v 1.10 2003/10/17 16:41:53 apg Exp $
    .....
    934 dnl Check for risky LessTif versions.
    935 dnl
    936 risky_lesstif=false
    937 ice_save_CPPFLAGS="$CPPFLAGS"
    938 CPPFLAGS="$CPPFLAGS $X_CFLAGS"
    939 AC_TRY_CPP([#include <Xm/Xm.h>
    940 #ifdef LESSTIF_VERSION
    941 #if LESSTIF_VERSION == 0 && LESSTIF_REVISION <= 86
    942 #error LessTif 0.86 or earlier
    943 #endif
    944 #endif], risky_lesstif=false, risky_lesstif=true)  
    945 CPPFLAGS="$ice_save_CPPFLAGS"
    946 dnl


Thanks,
Robert
-----Original Message-----
From: Arnaud Desitter [mailto:address@hidden 
Sent: 25 November 2003 16:50
To: Atwood, Robert C
Subject: Re: Segfault when a gnuplot graph is closed?



----- Original Message ----- 
From: "Atwood, Robert C" <address@hidden>
To: "'Arnaud Desitter'" <address@hidden>
Sent: Tuesday, November 25, 2003 4:23 PM
Subject: RE: Segfault when a gnuplot graph is closed?


>
> Okay, I'll try that. At first I did not realize that I could do this, 
> I
kept
> getting messages from configure that lesstif was required, because I 
> had
not
> installed the openmotif-devel RPM.  A small suggestion: if the Xm.h 
> file
is
> not found at all, the message would be better if it did not 
> specifically request the user to install lesstif. I am sorry I have 
> never used
'configure
> ' myself or I would try to fix it myself..

Which message ? Difficult to improve anything without knowing that. Relevant
files in CVS repository may be configure.ac and acinclude.m4.

As well, "configure --help" is informative IMO.

Regards,