= Autotool 環境設定及範例筆記 =
== 目標 ==
將寫好的程式碼透過以下指令就可編譯.安裝及使用
{{{
#!text
1. ./configure
2. make
3. make install
}}}

=== 第一階段：寫好source code及 Makefile ===

=== Step2. 編輯程式碼 ===
1. 參考[http://markuskimius.wikidot.com/programming:tut:autotools:2 autotool tutorial][[BR]]
2. 新增hello.c[[BR]]
{{{
#!text
/* hello.c: A standard "Hello, world!" program */
#include <stdio.h>
int main(int argc, char* argv[])
{
       printf("Hello, world!\n");
       return ;
}
}}}

3. 編輯Makefile(註：指令前的空白為<TAB>)[[BR]]
{{{
#!text
# Makefile: A standard Makefile for hello.c

all:
        gcc hello.c -o hello
clean:
        rm -f hello
}}}

=== Step3. 執行make，產生執行檔 ===
 * 執行
{{{
$ make
}}}

 * 步驟結束後目錄下會有以下檔案: hello.c hello Makefile


=== 第二階段：使用autoconf產生安裝及設定檔 ===
==== Step1. 工具取得及安裝 ====
1. 工具取得 [ftp://ftp.ntu.edu.tw/gnu/autoconf/autoconf-2.68.tar.gz autoconf下載(v2.68)]
2. 安裝(步驟略)

==== Step2. autoscan ====
 * 此一步驟為讓系統自動產生 configure.scan
 * 將產生的configure.scan更名為configure.ac，以便日後自行修改configure時不會被覆寫掉
 * 將Makefile 更名為 Makefile.in 做為日後修改的樣板
==== Step3. autoconf ====
 * 產生configure的可執行檔
 * 執行configure
{{{
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
configure: creating ./config.status
config.status: creating Makefile
config.status: error: cannot find input file: `config.h.in'
}}}
 * 錯誤訊息：因為無法找到header檔
==== Step4. autoheader ====
 * 執行 autoheader
 * 產生header檔
 * 執行configure
{{{
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
configure: creating ./config.status
config.status: creating Makefile
config.status: creating config.h
}}}

=== 第三階段：修改Source Code並支援 protable ===
==== Step1. 修改hello.c ====
{{{
#!text
/* hello.c: A program to show the time since the Epoch */
 
#include <stdio.h>
#include <sys/time.h>
 
int main(int argc, char* argv[])
{
   double sec;
   struct timeval tv;
 
   gettimeofday(&tv, NULL);
   sec = tv.tv_sec;
   sec += tv.tv_usec / 1000000.0;
 
   printf("%f\n", sec);
 
   return 0;
}
}}}

==== Step2. 更新設定檔 ===
{{{
$ autoscan
$ mv configure.scan configure.ac
$ autoconf
$ autoheader
$ ./configure
}}}

==== Step3. 修改source code使其支援protable ====
{{{
#!text
/* hello.c: A program to show the time since the Epoch */
 
#include <stdio.h>
#include "config.h"
 
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#else
#include <time.h>
#endif
 
double get_sec_since_epoch()
{
   double sec;
 
   #ifdef HAVE_GETTIMEOFDAY
      struct timeval tv;
 
      gettimeofday(&tv, NULL);
      sec = tv.tv_sec;
      sec += tv.tv_usec / 1000000.0;
   #else
      sec = time(NULL);
   #endif
 
   return sec;
}
 
int main(int argc, char* argv[])
{
   printf("%f\n", get_sec_since_epoch());
 
   return 0;
}
}}}

==== Step4. 編譯及執行 ====
{{{
$ autoscan
$ ./configure
$ make clean all
$ ./hello 
}}}

=== 第四階段：auto make ===
 * [http://ftp.gnu.org/gnu/automake/automake-1.11.1.tar.gz 下載]