Here is how we can recreate amhello-1.0.tar.gz from scratch. The package is simple enough so that we will only need to write 5 files. (You may copy them from the final amhello-1.0.tar.gz that is distributed with Automake if you do not want to write them.)
Create the following files in an empty directory.
~/amhello % cat src/main.c
#include <config.h>
#include <stdio.h>
int
main (void)
{
puts ("Hello World!");
puts ("This is " PACKAGE_STRING ".");
return 0;
}
~/amhello % cat README This is a demonstration package for GNU Automake. Type 'info Automake' to read the Automake manual.
~/amhello % cat src/Makefile.am bin_PROGRAMS = hello hello_SOURCES = main.c ~/amhello % cat Makefile.am SUBDIRS = src dist_doc_DATA = README
configure script.
~/amhello % cat configure.ac AC_INIT([amhello], [1.0], [bug-automake@gnu.org]) AM_INIT_AUTOMAKE([-Wall -Werror foreign]) AC_PROG_CC AC_CONFIG_HEADERS([config.h]) AC_CONFIG_FILES([ Makefile src/Makefile ]) AC_OUTPUT
Once you have these five files, it is time to run the Autotools to
instantiate the build system. Do this using the autoreconf
command as follows:
~/amhello % autoreconf --install configure.ac: installing './install-sh' configure.ac: installing './missing' src/Makefile.am: installing './depcomp'
At this point the build system is complete.
In addition to the three scripts mentioned in its output, you can see
that autoreconf created four other files: configure,
config.h.in, Makefile.in, and src/Makefile.in.
The latter three files are templates that will be adapted to the
system by configure under the names config.h,
Makefile, and src/Makefile. Let’s do this:
~/amhello % ./configure checking for a BSD-compatible install... /usr/bin/install -c checking whether build environment is sane... yes checking for gawk... no checking for mawk... mawk checking whether make sets $(MAKE)... yes checking for gcc... gcc checking for C compiler default output file name... a.out checking whether the C compiler works... yes checking whether we are cross compiling... no checking for suffix of executables... checking for suffix of object files... o checking whether we are using the GNU C compiler... yes checking whether gcc accepts -g... yes checking for gcc option to accept ISO C89... none needed checking for style of include used by make... GNU checking dependency style of gcc... gcc3 configure: creating ./config.status config.status: creating Makefile config.status: creating src/Makefile config.status: creating config.h config.status: executing depfiles commands
You can see Makefile, src/Makefile, and config.h
being created at the end after configure has probed the
system. It is now possible to run all the targets we wish
(see Standard Makefile Targets). For instance:
~/amhello % make … ~/amhello % src/hello Hello World! This is amhello 1.0. ~/amhello % make distcheck … ============================================= amhello-1.0 archives ready for distribution: amhello-1.0.tar.gz =============================================
Note that running autoreconf is only needed initially when
the GNU Build System does not exist. When you later change some
instructions in a Makefile.am or configure.ac, the
relevant part of the build system will be regenerated automatically
when you execute make.
autoreconf is a script that calls autoconf,
automake, and a bunch of other commands in the right order.
If you are beginning with these tools, it is not important to figure
out in which order all of these tools should be invoked and why. However,
because Autoconf and Automake have separate manuals, the important
point to understand is that autoconf is in charge of
creating configure from configure.ac, while
automake is in charge of creating Makefile.ins from
Makefile.ams and configure.ac. This should at least
direct you to the right manual when seeking answers.