RE: How are env variables passed to the compilation process

[Andy Falanga (afalanga)]

> -----Original Message-----
> From: Gavin Smith [mailto:address@hidden
> Sent: Thursday, March 12, 2015 9:09 AM
> To: Andy Falanga (afalanga)
> Cc: address@hidden
> Subject: Re: How are env variables passed to the compilation process
> 
> On 10 March 2015 at 22:04, Andy Falanga (afalanga)
> <address@hidden> wrote:
> > I'm trying to figure out how things like CXXFLAGS and CFLAGS get
> passed to ultimate point of compilation.  I thought I had it down but
> something that just happened recently has me wondering.  I've gotten my
> project building now using automake/autoconf/etc. (what I understand to
> be the autotools).  Now, the first target system I'm building on builds
> the code just fine but the library caused a segmentation violation.
> I'd like to debug.
> >
> > I go through the list of output made by the build process and
> discover that the build process didn't do what seems to be the
> "standard" options, "-O2 -g".   Neither of these were used.  So, I
> thought I'd add them.  I did this:
> >
> > make clean
> > ./configure CFLAGS="-ggdb -O0" CXXFLAGS="-ggdb -O2"
> > make
> >
> > Much to my surprise, the "-ggdb -O0" didn't appear then either.  Did
> I miss something?  Isn't this how they are set?
> >
> To get a hint of where it has gone wrong, have a look in the "Makefile"
> file that is produced by the configure script. It should have a lines
> like
> 
> CFLAGS = -ggdb -O0
> 
> in it. If it does, there is something wrong in the rest of the
> Makefile, so the problem is with the "Makefile.am" file. If it says
> something else, the value of CFLAGS is not being set properly by the
> configure script, so the problem is with the "configure.ac" file.

Ah, perfect.  Thank you for the tip.