Miscellaneous Autoconf Weirdness

[Drummonds, Scott B]

Hi, everyone,

I've performer further research on the problem described in the "Failing
C Header Checks" thread and have found something in Autoconf's behavior
that I don't understand.  I chalk this up to my misunderstaning of macro
languages, Autoconf, or both.

If I define a macro, let's say, "SCOTT", like so:

  AC_DEFUN([SCOTT],[
    echo "In macro SCOTT"
    ...
  ])

Then I put in 'configure.in' (old build environment is using the old
file name):
  echo "Calling SCOTT"
  SCOTT
  echo "Returned from SCOTT"

How is it possible that all of the following sequence--that I am
observing in my build environment--is ocurring?  I don't understand how
this setup works that additional code is inserted and executed between
the macro call and the execution of the first line in its body.  Would
someone set me straight?

<quote>
Calling SCOTT
checking for style of include used by make... GNU
checking how to run the C preprocessor...
/usr/intel/pkgs/gcc/2.95.3/bin/gcc -E
checking for egrep... grep -E
checking for non-GNU ld... /usr/bin/ld
checking if the linker (/usr/bin/ld) is GNU ld... yes
checking for /usr/bin/ld option to reload object files... -r
checking for BSD-compatible nm... /usr/bin/nm -B
checking for a sed that does not truncate output... ./configure: -g:
command not found
/usr/intel/bin/gsed
checking whether ln -s works... yes
checking how to recognise dependent libraries... pass_all
checking command to parse /usr/bin/nm -B output... failed
checking for ANSI C header files... no
checking for sys/types.h... no
checking for sys/stat.h... no
checking for stdlib.h... no
checking for string.h... no
checking for memory.h... no
[... many more checks deleted ...]
In macro SCOTT
...
</quote>


Thanks,
Scott