I know there are a lot of other autoconf examples out there, but these
are mine. The process of creating the examples is me learning about
autoconf. I'm a long way from my first attempt at writing autoconf
for netcat in 1999 before netcat was rewritten.
I have started pushing my examples to github. I would like it if the code in my examples could be used in any project without attribution. I just don't want the collection as a whole to get taken without attribution.
https://github.com/schwehr/autoconf_samples
This example is a stripped down C++ library with a single function and builds a binary that uses that library. I'm a little surprised that it does a static link by default. I'm trying to increment simple_lib just a little beyond the endian example.
The Makefile.am gets much more complicated. I'm not 100% sure that I have this right. If anyone has a better way to specify and track the library version info, please let me know. I do know that you are supposed to refer to the locally built libraries with libFOO.la (not -lFOO) and let autoconf/automake do the right thing.
I have two helper scripts. First is and extention of the autogen.sh script. It makes sure there is an m4 directory and tells autoreconf to put what it can in that directory.
I have started pushing my examples to github. I would like it if the code in my examples could be used in any project without attribution. I just don't want the collection as a whole to get taken without attribution.
https://github.com/schwehr/autoconf_samples
This example is a stripped down C++ library with a single function and builds a binary that uses that library. I'm a little surprised that it does a static link by default. I'm trying to increment simple_lib just a little beyond the endian example.
ls -l total 56 -rw-r--r-- 1 schwehr 5000 0 Jun 30 15:42 AUTHORS -rw-r--r-- 1 schwehr 5000 0 Jun 30 15:42 ChangeLog -rw-r--r-- 1 schwehr 5000 271 Jun 30 15:54 Makefile.am -rw-r--r-- 1 schwehr 5000 0 Jun 30 15:42 NEWS -rw-r--r-- 1 schwehr 5000 0 Jun 30 15:42 README -rwxr-xr-x 1 schwehr 5000 99 Jun 30 15:41 autogen.sh -rwxr-xr-x 1 schwehr 5000 140 Jun 30 16:04 clean.sh -rw-r--r-- 1 schwehr 5000 401 Jun 30 18:35 configure.ac -rw-r--r-- 1 schwehr 5000 102 Jun 30 16:08 simple.cc -rw-r--r-- 1 schwehr 5000 14 Jun 30 15:46 simple.h -rw-r--r-- 1 schwehr 5000 60 Jun 30 15:52 simple_prog.ccFirst, the configure:
AC_PREREQ([2.65])
LT_PREREQ([2.4.2])
AC_CONFIG_MACRO_DIR(m4)
AC_INIT([simple],[1.0])
LT_INIT
AM_INIT_AUTOMAKE
AM_MAINTAINER_MODE
AC_PROG_CXX
AC_CONFIG_FILES([Makefile])
AC_CONFIG_HEADERS([config.h])
AC_OUTPUT
AS_ECHO
AS_ECHO([Results])
AS_ECHO
AS_ECHO(["$PACKAGE_STRING will be installed in: ${prefix}"])
AS_ECHO(["Use shared libs: $enable_shared"])
AS_ECHO(["Use static libs: $enable_static"])
A quick tour of the changes... First, I added libtool macros. The
LT_INIT sets up everything needed to build static and shared
libraries. I added AC_CONFIG_MACRO_DIR to try to hide more of the
autoconf/libtools stuff under a m4 directory. Then I added
AM_MAINTAINER_MODE, but that doesn't actually seem to add much. Then
I switch the AM C compiler macro with AC_PROG_CXX. Finally, I wanted
to demonstrate having a results summary section. The autoconf manuals
say that we should not use the shell echo command directly, so I used
AS_ECHO to print out the key results of the configure stage.
The Makefile.am gets much more complicated. I'm not 100% sure that I have this right. If anyone has a better way to specify and track the library version info, please let me know. I do know that you are supposed to refer to the locally built libraries with libFOO.la (not -lFOO) and let autoconf/automake do the right thing.
ACLOCAL_AMFLAGS = -I m4 include_HEADERS = simple.h lib_LTLIBRARIES = libsimple.la libsimple_la_LDFLAGS = -no-undefined -version-info 0:0:0 libsimple_la_SOURCES = simple.cc bin_PROGRAMS = simple_prog simple_prog_SOURCES = simple_prog.cc simple_prog_LDADD = simple.loI'm using a fully automatic config.h (I have no config.h.in), so I need to include the config.h in simple.cc:
#include "config.h"
#include <iostream>
void hello() {
std::cout << "Hello world from a lib\n";
}
Pretty boring library, but it does demonstrate the library.
I have two helper scripts. First is and extention of the autogen.sh script. It makes sure there is an m4 directory and tells autoreconf to put what it can in that directory.
#!/bin/bash if [ ! -d m4 ]; then echo mkdir mkdir m4 fi autoreconf --force --install -I m4The 2nd script is clean. It uses the maintainer-clean in the Makefile, but there is still a lot of autogenerated stuff, so I also rm the left overs.
#!/bin/bash make maintainer-clean rm -rf INSTALL Makefile.in aclocal.m4 compile config.* rm -rf configure depcomp install-sh ltmain.sh m4 missingTo build everything, here is what I do:
./autogen.sh mkdir libtoolize: putting auxiliary files in `.'. libtoolize: copying file `./ltmain.sh' libtoolize: putting macros in AC_CONFIG_MACRO_DIR, `m4'. libtoolize: copying file `m4/libtool.m4' libtoolize: copying file `m4/ltoptions.m4' libtoolize: copying file `m4/ltsugar.m4' libtoolize: copying file `m4/ltversion.m4' libtoolize: copying file `m4/lt~obsolete.m4' configure.ac:7: installing './config.guess' configure.ac:7: installing './config.sub' configure.ac:9: installing './install-sh' configure.ac:9: installing './missing' Makefile.am: installing './INSTALL' Makefile.am: installing './COPYING' using GNU General Public License v3 file Makefile.am: Consider adding the COPYING file to the version control system Makefile.am: for your code, to avoid questions about which license your project uses Makefile.am: installing './depcomp' ./configure --enable-maintainer-mode --enable-dependency-tracking checking build system type... x86_64-apple-darwin12.4.0 checking host system type... x86_64-apple-darwin12.4.0 checking how to print strings... printf checking for gcc... gcc checking whether the C compiler works... yes checking for C compiler default output file name... a.out checking for suffix of executables... checking whether we are cross compiling... no 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 a sed that does not truncate output... /sw/bin/sed checking for grep that handles long lines and -e... /usr/bin/grep checking for egrep... /usr/bin/grep -E checking for fgrep... /usr/bin/grep -F checking for ld used by gcc... /usr/llvm-gcc-4.2/libexec/gcc/i686-apple-darwin11/4.2.1/ld checking if the linker (/usr/llvm-gcc-4.2/libexec/gcc/i686-apple-darwin11/4.2.1/ld) is GNU ld... no checking for BSD- or MS-compatible name lister (nm)... /usr/bin/nm checking the name lister (/usr/bin/nm) interface... BSD nm checking whether ln -s works... yes checking the maximum length of command line arguments... 196608 checking whether the shell understands some XSI constructs... yes checking whether the shell understands "+="... yes checking how to convert x86_64-apple-darwin12.4.0 file names to x86_64-apple-darwin12.4.0 format... func_convert_file_noop checking how to convert x86_64-apple-darwin12.4.0 file names to toolchain format... func_convert_file_noop checking for /usr/llvm-gcc-4.2/libexec/gcc/i686-apple-darwin11/4.2.1/ld option to reload object files... -r checking for objdump... no checking how to recognize dependent libraries... pass_all checking for dlltool... no checking how to associate runtime and link libraries... printf %s\n checking for ar... ar checking for archiver @FILE support... no checking for strip... strip checking for ranlib... ranlib checking for gawk... gawk checking command to parse /usr/bin/nm output from gcc object... ok checking for sysroot... no checking for mt... no [snip] checking how to run the C++ preprocessor... g++ -E checking for ld used by g++... /usr/llvm-gcc-4.2/libexec/gcc/i686-apple-darwin11/4.2.1/ld checking if the linker (/usr/llvm-gcc-4.2/libexec/gcc/i686-apple-darwin11/4.2.1/ld) is GNU ld... no checking whether the g++ linker (/usr/llvm-gcc-4.2/libexec/gcc/i686-apple-darwin11/4.2.1/ld) supports shared libraries... yes checking for g++ option to produce PIC... -fno-common -DPIC checking if g++ PIC flag -fno-common -DPIC works... yes checking if g++ static flag -static works... no checking if g++ supports -c -o file.o... yes checking if g++ supports -c -o file.o... (cached) yes checking whether the g++ linker (/usr/llvm-gcc-4.2/libexec/gcc/i686-apple-darwin11/4.2.1/ld) supports shared libraries... yes checking dynamic linker characteristics... darwin12.4.0 dyld checking how to hardcode library paths into programs... immediate checking dependency style of g++... gcc3 checking that generated files are newer than configure... done configure: creating ./config.status config.status: creating Makefile config.status: creating config.h config.status: executing libtool commands config.status: executing depfiles commands Results simple 1.0 will be installed in: /usr/local Use shared libs: yes make make all-am /bin/sh ./libtool --tag=CXX --mode=compile g++ -DHAVE_CONFIG_H -I. -g -O2 -MT simple.lo -MD -MP -MF .deps/simple.Tpo -c -o simple.lo simple.cc libtool: compile: g++ -DHAVE_CONFIG_H -I. -g -O2 -MT simple.lo -MD -MP -MF .deps/simple.Tpo -c simple.cc -fno-common -DPIC -o .libs/simple.o libtool: compile: g++ -DHAVE_CONFIG_H -I. -g -O2 -MT simple.lo -MD -MP -MF .deps/simple.Tpo -c simple.cc -o simple.o >/dev/null 2>&1 mv -f .deps/simple.Tpo .deps/simple.Plo /bin/sh ./libtool --tag=CXX --mode=link g++ -g -O2 -no-undefined -version-info 0:0:0 -o libsimple.la -rpath /usr/local/lib simple.lo libtool: link: g++ -dynamiclib -o .libs/libsimple.0.dylib .libs/simple.o -O2 -install_name /usr/local/lib/libsimple.0.dylib -compatibility_version 1 -current_version 1.0 -Wl,-single_module libtool: link: (cd ".libs" && rm -f "libsimple.dylib" && ln -s "libsimple.0.dylib" "libsimple.dylib") libtool: link: ar cru .libs/libsimple.a simple.o libtool: link: ranlib .libs/libsimple.a libtool: link: ( cd ".libs" && rm -f "libsimple.la" && ln -s "../libsimple.la" "libsimple.la" ) g++ -DHAVE_CONFIG_H -I. -g -O2 -MT simple_prog.o -MD -MP -MF .deps/simple_prog.Tpo -c -o simple_prog.o simple_prog.cc mv -f .deps/simple_prog.Tpo .deps/simple_prog.Po /bin/sh ./libtool --tag=CXX --mode=link g++ -g -O2 -o simple_prog simple_prog.o simple.lo libtool: link: g++ -g -O2 -o simple_prog simple_prog.o .libs/simple.o -Wl,-bind_at_loadNow the results:
otool -L simple_prog simple_prog: /usr/lib/libstdc++.6.dylib (compatibility version 7.0.0, current version 56.0.0) /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 169.3.0) ./simple_prog Hello world from a lib ls -l .libs/ total 144 -rwxr-xr-x 1 schwehr 5000 9508 Jun 30 19:20 libsimple.0.dylib -rw-r--r-- 1 schwehr 5000 23376 Jun 30 19:20 libsimple.a lrwxr-xr-x 1 schwehr 5000 17 Jun 30 19:20 libsimple.dylib -> libsimple.0.dylib lrwxr-xr-x 1 schwehr 5000 15 Jun 30 19:20 libsimple.la -> ../libsimple.la -rw-r--r-- 1 schwehr 5000 922 Jun 30 19:20 libsimple.lai -rw-r--r-- 1 schwehr 5000 23184 Jun 30 19:20 simple.o