(automake-1.16.info)Creating amhello

---

Next: amhello's configure.ac Setup Explained Up: Hello World

---

Enter node , (file) or (file)node

2.4.1 Creating ‘amhello-1.0.tar.gz’
-----------------------------------

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.

   • ‘src/main.c’ is the source file for the ‘hello’ program.  We store
     it in the ‘src/’ subdirectory, because later, when the package
     evolves, it will ease the addition of a ‘man/’ directory for man
     pages, a ‘data/’ directory for data files, etc.
          ~/amhello % cat src/main.c
          #include <config.h>
          #include <stdio.h>

          int
          main (void)
          {
            puts ("Hello World!");
            puts ("This is " PACKAGE_STRING ".");
            return 0;
          }

   • ‘README’ contains some very limited documentation for our little
     package.
          ~/amhello % cat README
          This is a demonstration package for GNU Automake.
          Type 'info Automake' to read the Automake manual.

   • ‘Makefile.am’ and ‘src/Makefile.am’ contain Automake instructions
     for these two directories.

          ~/amhello % cat src/Makefile.am
          bin_PROGRAMS = hello
          hello_SOURCES = main.c
          ~/amhello % cat Makefile.am
          SUBDIRS = src
          dist_doc_DATA = README

   • Finally, ‘configure.ac’ contains Autoconf instructions to create
     the ‘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'
     configure.ac: installing './compile'
     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 (Note: Standard 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.in’s
from ‘Makefile.am’s and ‘configure.ac’.  This should at least direct you
to the right manual when seeking answers.