如我们要生成交叉编译给ARM CPU使用的共享库,这里假设我们要使用的编译器为arm-none-linux-gnueabi-gcc，并且我们最终在ARM板上执行时，要把库安装到目标板的/usr/local/armrx2d目录中去。可以这样配置:
#
#
# 利用libtool自动生成动态库
#
1. autoscan命令在当前目录生成configure.scan文件, 内容为:
# -*- Autoconf -*-
# Process this file with autoconf to produce a configure script.
AC_PREREQ(2.57)
AC_INIT(FULL-PACKAGE-NAME, VERSION, BUG-REPORT-ADDRESS)
AC_CONFIG_SRCDIR([src/bot.h])
AC_CONFIG_HEADER([config.h])
# Checks for programs.
AC_PROG_CXX
AC_PROG_CC
# Checks for libraries.
# Checks for header files.
AC_HEADER_STDC
AC_CHECK_HEADERS([limits.h malloc.h stdlib.h string.h unistd.h])
# Checks for typedefs, structures, and compiler characteristics.
AC_HEADER_STDBOOL
AC_C_CONST
AC_C_INLINE
# Checks for library functions.
AC_FUNC_MALLOC
AC_FUNC_REALLOC
AC_CHECK_FUNCS([memset strcasecmp strchr strdup])
AC_OUTPUT
将其该名为configure.ac 然后修改:
configure.ac 文件是 autoconf 的输入文件，经过 autoconf 处理，展开里面的 m4宏，
输出的是 configure 脚本。
第 4 行声明本文件要求的 autoconf 版本，因为本例使用了新版本 2.57，所以在此注明。
第 5 行 AC_INIT 宏用来定义软件的名称和版本等信息
AC_INIT([test], 1.0, [email]linhanzu@gmail.com[/email])
增加版本信息(为生成lib库做准备)
lt_major=1
lt_age=1
lt_revision=12
dist_version=0.1.12
AM_INIT_AUTOMAKE(test, $dist_version) //自动生成Makefile文件
增加宏, 打开共享库
AC_PROG_LIBTOOL
# Check for dl
DL_PRESENT=""
AC_CHECK_LIB( dl, dlopen, DL_PRESENT="yes",, $DL_LIBS -ldl )
if test "x$DL_PRESENT" = "xyes"; then
AC_DEFINE(HAVE_LIBDL, 1, [Define if DL lib is present])
DL_LIBS="-ldl"
AC_SUBST(DL_LIBS)
fi
# Check for libm
M_PRESENT=""
AC_CHECK_LIB( m, sin, M_PRESENT="yes",, $M_LIBS -lm )
if test "x$M_PRESENT" = "xyes"; then
AC_DEFINE(HAVE_LIBM, 1, [Define if libm is present])
M_LIBS="-lm"
AC_SUBST(M_LIBS)
fi
增加依赖库，这里就仅仅列举了pthread库，生成的Makefile会自动加上-pthread
# Check for pthread
PTHREAD_PRESENT=""
AC_CHECK_LIB( pthread, pthread_create, PTHREAD_PRESENT="yes",, $PTHREAD_LIBS
-lpthread )
if test "x$PTHREAD_PRESENT" = "xyes"; then
AC_DEFINE(HAVE_LIBPTHREAD, 1, [Define if libpthread is present])
PTHREAD_LIBS="-lpthread"
AC_SUBST(PTHREAD_LIBS)
fi
要生成项目工程目录和其它目录下的Makefile 文件, 必需加入
AM_CONFIG_FILES的宏:
例如: AC_CONFIG_FILES([Makefile
src/Makefile
data/Makefile
docs/Makefile])
修改完后Makefile.ac如下:
# -*- Autoconf -*-
# Process this file with autoconf to produce a configure script.
AC_PREREQ(2.57)
AC_INIT([test],[1.0],[[email]arne_caspari@users.sourceforge.net[/email]])
AM_CONFIG_HEADER(config.h)
lt_major=1
lt_age=1
lt_revision=12
dist_version=0.1.12
AM_INIT_AUTOMAKE(test, $dist_version)
AC_SUBST(lt_major)
AC_SUBST(lt_revision)
AC_SUBST(lt_age)
# Checks for programs.
#AC_PROG_CC
#AC_PROG_INSTALL
#AC_PROG_LN_S
#AC_PROG_LIBTOOL
AM_PROG_LIBTOOL
# Checks for libraries.
pkg_modules="gtk+-2.0 >= 2.0.0"
PKG_CHECK_MODULES(GTK_PACKAGE, [$pkg_modules], HAVE_GTK2="yes", HAVE_GTK2="no" )
AC_SUBST(GTK_PACKAGE_CFLAGS)
AC_SUBST(GTK_PACKAGE_LIBS)
# Check for dl
DL_PRESENT=""
AC_CHECK_LIB( dl, dlopen, DL_PRESENT="yes",, $DL_LIBS -ldl )
if test "x$DL_PRESENT" = "xyes"; then
AC_DEFINE(HAVE_LIBDL, 1, [Define if DL lib is present])
DL_LIBS="-ldl"
AC_SUBST(DL_LIBS)
fi
# Check for libm
M_PRESENT=""
AC_CHECK_LIB( m, sin, M_PRESENT="yes",, $M_LIBS -lm )
if test "x$M_PRESENT" = "xyes"; then
AC_DEFINE(HAVE_LIBM, 1, [Define if libm is present])
M_LIBS="-lm"
AC_SUBST(M_LIBS)
fi
# Check for pthread
PTHREAD_PRESENT=""
AC_CHECK_LIB( pthread, pthread_create, PTHREAD_PRESENT="yes",, $PTHREAD_LIBS
-lpthread )
if test "x$PTHREAD_PRESENT" = "xyes"; then
AC_DEFINE(HAVE_LIBPTHREAD, 1, [Define if libpthread is present])
PTHREAD_LIBS="-lpthread"
AC_SUBST(PTHREAD_LIBS)
fi
# Checks for header files.
#AC_HEADER_DIRENT
#AC_HEADER_STDC
#AC_CHECK_HEADERS([fcntl.h stdlib.h string.h sys/time.h unistd.h])
# Checks for typedefs, structures, and compiler characteristics.
#AC_TYPE_PID_T
#AC_TYPE_SIZE_T
#AC_HEADER_TIME
# Checks for library functions.
#AC_FUNC_CLOSEDIR_VOID
#AC_FUNC_MALLOC
#AC_CHECK_FUNCS([memset strstr])
AC_CONFIG_FILES([Makefile
src/Makefile
data/Makefile
doc/Makefile])
AC_OUTPUT
2.生成各目录下的Makefile.am文件
./Makefile.am //工程目录下
SUBDIR = src data doc
../src/Makefile.am //源码目录下
MAINTAINERCLEANFILES = Makefile.in
INCLUDES = -I../include
CPPFLAGS=-DINSTALL_PREFIX="\"$(prefix)\""
lib_LTLIBRARIES = libtest.la
libtest_la_LDFLAGS = -version-info @lt_major@:@lt_revision@:@lt_age@
libtest_la_SOURCES = \
test.c \
test_private.h \
check_match.c \
check_match.h \
test_helpers.c \
test_helpers.h \
debug.h
libtest_la_LIBADD = \
@DL_LIBS@ \
@M_LIBS@
3. 生成autogen.sh脚本, 内容
#! /bin/sh
set -x
aclocal
autoheader
automake --foreign --add-missing --copy
autoconf
保存后修改权限 chmod a+x autogen.sh
3.运行脚本./autogen.sh, 生成configure脚本. 这里可能会遇到错误, 可以根据错误提示作相应修改.（注意：如果您修改了Makefile.am中的项，那么就得重新执行这一步）
4.运行./configure脚本.自动生成src目录下的makefile文件
5. 切换到目录src, 运行make 自动在当前目录下建立.libs文件, 编程生成的库文件就保存在该目录下.
make install 安装在默认目录 /usr/local/lib/下.
6.如果要生成其它的安装目录，Makefile.am就要这样写
MAINTAINERCLEANFILES = Makefile.in
INCLUDES = -I../include
lib_LTLIBRARIES = libtt.la
libdir = $(prefix)/lib/test //这个就是安装目录
libtt_la_LDFLAGS = -version-info @lt_major@:@lt_revision@:@lt_age@
libtt_la_LIBADD = @PTHREAD_LIBS@
libtt_la_SOURCES = \
tt.c \
video.c \
video.h
当然，Makefile中的语法规则中还有很多宏定义，您可以在Makefile的官方网站找到说明。
下一篇就打算写写条件编译的Makefile写法。