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

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​autotool tutorial
   
2. 新增hello.c
   

   /* 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>)
   

   # 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 ​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

Step1. 修改hello.c

/* 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

/* 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