C实战：项目构建Make,Automake,CMake

宗政金鹏

2023-12-01

http://blog.csdn.net/dc_726/article/details/48978849

C实战：项目构建Make,Automake,CMake

在本系列文章《C实战：强大的程序调试工具GDB》中我们简要学习了流行的调试工具GDB的使用方法。本文继续“C实战”的主题，对同样非常流行的构建工具Make的用法和原理一探究竟，并顺便看一下一些高级衍生产品。

1.Make基础

首先我们编写一个简单的C项目，以此项目在实战中学习Make的相关知识。更全面的介绍请参考官方手册。

<code class="language-bash hljs  has-numbering">cdai@vm /syspace/<span class="hljs-number">2</span>-ccpp/<span class="hljs-number">24</span>-pragmatic/build-tool/make $ tree
.
├── hello.c
├── hello.h
├── main.c
└── Makefile

<span class="hljs-number">0</span> directories, <span class="hljs-number">4</span> files</code><ul style="display: block;" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li><li>8</li></ul>

整个程序的逻辑非常简单：main.c中包含一个main方法，调用了hello.c中的sayHello()函数，打印了一句话到控制台上。

<code class="language-c hljs  has-numbering"><span class="hljs-comment">// cat main.c hello.h hello.c</span>
<span class="hljs-comment">// ----- main.c -----</span>
<span class="hljs-preprocessor">#include "hello.h"</span>

<span class="hljs-keyword">int</span> main(<span class="hljs-keyword">void</span>)
{
    sayHello(<span class="hljs-string">"Make"</span>);
    <span class="hljs-keyword">return</span> <span class="hljs-number">1</span>;
}

<span class="hljs-comment">// ----- hello.h -----</span>
<span class="hljs-preprocessor">#ifndef _HELLO_H_</span>
<span class="hljs-preprocessor">#define _HELLO_H_</span>

<span class="hljs-keyword">void</span> sayHello(<span class="hljs-keyword">char</span> *name);

<span class="hljs-preprocessor">#endif</span>

<span class="hljs-comment">// ----- hello.c -----</span>
<span class="hljs-preprocessor">#include "hello.h"</span>
<span class="hljs-preprocessor">#include <stdio.h></span>

<span class="hljs-keyword">void</span> sayHello(<span class="hljs-keyword">char</span> *name)
{
    <span class="hljs-built_in">printf</span>(<span class="hljs-string">"Hello, %s!\n"</span>, name);
}</code><ul style="display: block;" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li><li>8</li><li>9</li><li>10</li><li>11</li><li>12</li><li>13</li><li>14</li><li>15</li><li>16</li><li>17</li><li>18</li><li>19</li><li>20</li><li>21</li><li>22</li><li>23</li><li>24</li><li>25</li><li>26</li></ul>

1.1 基本语法

一个简单的Makefile包含很多规则(Rule)，每一条规则的语法结构由目标(Target)、先决条件(Prerequisite)、动作(Recipe)三部分组成：

目标：通常有两种命名方法，一是与要生成的可执行文件或目标文件同名，二是说明动作的目的，例如最常见的clean清理规则。对于第二种规则命名，为了避免与同名文件冲突，可以将目标名加入到.PHONY伪目标列表中。默认情况下，make执行Makefile中的第一个规则，此规则被称为最终目标
先决条件：先决条件是用来创建目标的输入文件，一个目标可以依赖多个先决条件
动作：动作由Make命令负责执行，可以包含多个命令，每个命令可以另起一行。一定要注意的是：命令必须以TAB开头！

<code class="language-Makefile hljs http has-numbering"><span class="hljs-attribute">target</span>: <span class="hljs-string">prerequisite</span>
    <span class="hljs-attribute">recipe</span></code><ul style="display: block;" class="pre-numbering"><li>1</li><li>2</li></ul>

下面就看一下示例项目的Makefile是什么样子的。在Makefile中有3个规则，其中目标main依赖于main.o和hello.o，利用gcc执行链接，这与我们的代码结构是相对应的。而main.o和hello.o则分别依赖于各自的源代码.c文件和hello.h头文件，并利用gcc -c执行编译。

<code class="language-Makefile hljs avrasm has-numbering"><span class="hljs-label">main:</span> main<span class="hljs-preprocessor">.o</span> hello<span class="hljs-preprocessor">.o</span>
    gcc -o main main<span class="hljs-preprocessor">.o</span> hello<span class="hljs-preprocessor">.o</span>

<span class="hljs-label">main.o:</span> main<span class="hljs-preprocessor">.c</span> hello<span class="hljs-preprocessor">.h</span>
    gcc -c main<span class="hljs-preprocessor">.c</span> -o main<span class="hljs-preprocessor">.o</span>

<span class="hljs-label">hello.o:</span> hello<span class="hljs-preprocessor">.c</span> hello<span class="hljs-preprocessor">.h</span>
    gcc -c hello<span class="hljs-preprocessor">.c</span> -o hello<span class="hljs-preprocessor">.o</span></code><ul style="display: block;" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li><li>8</li></ul>

1.2 实现原理

Make看似非常智能，其实它的原理就像其语法规则一样简单。

确定目标：如果没有指明，则执行最终目标，即第一个规则的目标
处理变量和规则：替换变量，推导隐式规则（下一节会学习）
生成依赖关系链：为所有目标生成依赖关系链
递归构建：从依赖链的底部向上，根据先决条件会有三种情况：
4.1 先决条件不存在，则执行规则中的命令
4.2 先决条件存在，且至少一个比目标“更新”，则执行规则中的命令重新生成
4.3 先决条件存在，且都比目标“更旧”，则什么都不做

了解了Make的原理，就看一下我们的示例项目Make的执行过程。可以看到，Make以第一个目标main作为构建目标，从关系链底部的main.o和hello.o开始构建，最终生成了可执行文件main。接下来就执行main，可以看到控制台输出了”Hello, Make!”，证明我们构建成功了！

<code class="language-bash hljs  has-numbering">cdai@vm /syspace/<span class="hljs-number">2</span>-ccpp/<span class="hljs-number">24</span>-pragmatic/build-tool/make $ make
gcc -c main.c -o main.o
gcc -c hello.c -o hello.o
gcc -o main main.o hello.o

cdai@vm /syspace/<span class="hljs-number">2</span>-ccpp/<span class="hljs-number">24</span>-pragmatic/build-tool/make $ ./main
Hello, Make!</code><ul style="display: block;" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li></ul>

再次执行make会看到“‘main’ is up to date.”的提示，说明Make检测到了没有发生任何修改。如果我们做一点改动，例如修改以下sayHello()函数中的输出，再执行Make就能看到hello.o和main被重新构建，而main.o规则的命令没有被执行。

<code class="language-bash hljs  has-numbering">cdai@vm /syspace/<span class="hljs-number">2</span>-ccpp/<span class="hljs-number">24</span>-pragmatic/build-tool/make $ make
make: <span class="hljs-string">'main'</span> is up to date.

cdai@vm /syspace/<span class="hljs-number">2</span>-ccpp/<span class="hljs-number">24</span>-pragmatic/build-tool/make $ make
gcc -c hello.c -o hello.o
gcc -o main main.o hello.o

cdai@vm /syspace/<span class="hljs-number">2</span>-ccpp/<span class="hljs-number">24</span>-pragmatic/build-tool/make $ ./main
Hello111, Make!</code><ul style="display: block;" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li><li>8</li><li>9</li></ul>

2.Make进阶

2.1 变量

在Makefile中，我们可以用变量来替换重复出现在先决条件或动作中的字符串。例如，对于前面我们的示例Makefile，最明显的问题就是gcc和main目标依赖的main.o和hello.o出现了多次，我们可以用变量将它们提取出来。同样地，我们也经常将链接和编译选项做成变量。

<code class="language-Makefile hljs avrasm has-numbering"><span class="hljs-keyword">LD</span>      = gcc
CC      = gcc
CFLAGS  = -Wall
OBJECTS = main<span class="hljs-preprocessor">.o</span> hello<span class="hljs-preprocessor">.o</span>


<span class="hljs-label">all:</span> main

<span class="hljs-label">main:</span> $(OBJECTS)
    $(<span class="hljs-keyword">LD</span>) -o main $(OBJECTS)

<span class="hljs-label">main.o:</span> main<span class="hljs-preprocessor">.c</span> hello<span class="hljs-preprocessor">.h</span>
    $(CC) $(CFLAGS) -c $< -o $@

<span class="hljs-label">hello.o:</span> hello<span class="hljs-preprocessor">.c</span> hello<span class="hljs-preprocessor">.h</span>
    $(CC) $(CFLAGS) -c hello<span class="hljs-preprocessor">.c</span> -o hello<span class="hljs-preprocessor">.o</span></code><ul style="display: block;" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li><li>8</li><li>9</li><li>10</li><li>11</li><li>12</li><li>13</li><li>14</li><li>15</li><li>16</li></ul>

执行一下make可以看到效果，我们提取出来的变量在执行之前都被替换到了正确的位置。

<code class="language-bash hljs  has-numbering">cdaih@vm /syspace/<span class="hljs-number">2</span>-ccpp/<span class="hljs-number">24</span>-pragmatic/build-tool/make $ make
gcc -Wall -c main.c -o main.o
gcc -Wall -c hello.c -o hello.o
gcc -o main main.o hello.o</code><ul style="display: block;" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li></ul>

2.2 隐式规则

使用Make编译.c源文件时，规则的命令和先决条件都可以简化，对于命令，我们不用明确指出，Make能够自动将.c编译成.o；对于先决条件，Make还会自动寻找.o对应的.c源文件，我们只需给出头文件即可。

<code class="language-Makefile hljs avrasm has-numbering"><span class="hljs-keyword">LD</span>      = gcc
OBJECTS = main<span class="hljs-preprocessor">.o</span> hello<span class="hljs-preprocessor">.o</span>


<span class="hljs-label">all:</span> main

<span class="hljs-label">main:</span> $(OBJECTS)
    $(<span class="hljs-keyword">LD</span>) -o main $(OBJECTS)

<span class="hljs-label">main.o:</span> hello<span class="hljs-preprocessor">.h</span>
<span class="hljs-label">hello.o:</span> hello<span class="hljs-preprocessor">.h</span></code><ul style="display: block;" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li><li>8</li><li>9</li><li>10</li><li>11</li></ul>

我们将main.o和hell.o的规则都做了简化，执行一下可以看到Make自动执行了cc -c，并根据目标找到了对应的源文件main.c和hello.c。

<code class="language-bash hljs  has-numbering">cdaih@vm /syspace/<span class="hljs-number">2</span>-ccpp/<span class="hljs-number">24</span>-pragmatic/build-tool/make $ make
cc    -c -o main.o main.c
cc    -c -o hello.o hello.c
gcc -o main main.o hello.o</code><ul style="display: block;" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li></ul>

2.3 模式规则

隐式规则虽然很方便，但有时我们还想自己控制规则，这时我们可以使用模式规则。老Make支持.c.o这种规则定义，而新Make一般推荐使用模式规则，因为它支持模式匹配，更灵活、更强大！例如，我们定义目标名匹配%.o和先决条件匹配%.c的话，就执行编译命令。这样main.o和hello.o被简化的同时，我们还对其进行了精确的控制。

<code class="language-Makefile hljs avrasm has-numbering"><span class="hljs-keyword">LD</span>      = gcc
CC      = gcc
CFLAGS  = -Wall
OBJECTS = main<span class="hljs-preprocessor">.o</span> hello<span class="hljs-preprocessor">.o</span>

%<span class="hljs-preprocessor">.o</span>: %<span class="hljs-preprocessor">.c</span>
    $(CC) $(CFLAGS) -c $< -o $@

<span class="hljs-label">all:</span> main

<span class="hljs-label">main:</span> $(OBJECTS)
    $(<span class="hljs-keyword">LD</span>) -o main $(OBJECTS)

<span class="hljs-label">main.o:</span> main<span class="hljs-preprocessor">.c</span> hello<span class="hljs-preprocessor">.h</span>
<span class="hljs-label">hello.o:</span> hello<span class="hljs-preprocessor">.c</span> hello<span class="hljs-preprocessor">.h</span></code><ul style="display: block;" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li><li>8</li><li>9</li><li>10</li><li>11</li><li>12</li><li>13</li><li>14</li><li>15</li></ul>

执行一下看看效果。

<code class="language-bash hljs  has-numbering">cdaih@vm /syspace/<span class="hljs-number">2</span>-ccpp/<span class="hljs-number">24</span>-pragmatic/build-tool/make $ make
gcc -Wall -c main.c -o main.o
gcc -Wall -c hello.c -o hello.o
gcc -o main main.o hello.o</code><ul style="display: block;" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li></ul>

3.Makefile生成工具

Make的流行也带动起一批自动生成Makefile的工具，目的就是进一步减轻项目构建中的工作量，让我们程序员全身心投入到开发之中。在这些工具中，不得不提Automake和CMake。

3.1 Automake

Automake其实是一系列工具集Autotools中的一员，要想发挥Automake的威力，需要配合使用Autotools中的其他工具，例如autoscan、aclocal、autoconf和autoheader。在下面的Automake构建流程中，能看到这些工具的身影。

autoscan：生成configure.scan
configure.in：将configure.scan重命名为configure.in后，修改内容。重点是AM_INIT_AUTOMAKE和AC_CONFIG_FILES两项，如果没配置的话，下一步的aclocal是无法产生aclocal.m4的
aclocal：生成aclocal.m4
autoconf：生成configure
autoheader：生成config.h.in，使程序可移植
Makefile.am：手动编写Makefile.am。bin_PROGRAMS指定最终生成可执行文件的名称，helloworld_SOURCES指定所有源文件
NEWS AUTHORS README ChangeLog：手动创建
automake：执行automake -a生成Makefile.in
configure：执行./configure生成Makefile

<code class="hljs coffeescript has-numbering"><span class="hljs-comment"># Step 1:</span>
[root<span class="hljs-property">@vm</span> automaketest]<span class="hljs-comment"># autoscan</span>

<span class="hljs-comment"># Step 2:</span>
[root<span class="hljs-property">@vm</span> automaketest]<span class="hljs-comment"># mv configure.scan configure.in</span>
[root<span class="hljs-property">@vm</span> automaketest]<span class="hljs-comment"># cat configure.in</span>
<span class="hljs-comment">#                                               -*- Autoconf -*-</span>
<span class="hljs-comment"># Process this file with autoconf to produce a configure script.</span>

AC_PREREQ([<span class="hljs-number">2.63</span>])
AC_INIT(main, <span class="hljs-number">1.0</span>)
AM_INIT_AUTOMAKE(main, <span class="hljs-number">1.0</span>)
AC_CONFIG_SRCDIR([main.c])
AC_CONFIG_HEADERS([config.h])

<span class="hljs-comment"># Checks for programs.</span>
AC_PROG_CC

<span class="hljs-comment"># Checks for libraries.</span>

<span class="hljs-comment"># Checks for header files.</span>

<span class="hljs-comment"># Checks for typedefs, structures, and compiler characteristics.</span>

<span class="hljs-comment"># Checks for library functions.</span>

AC_CONFIG_FILES([Makefile])
AC_OUTPUT

<span class="hljs-comment"># Step 3:</span>
[root<span class="hljs-property">@vm</span> automaketest]<span class="hljs-comment"># aclocal</span>

<span class="hljs-comment"># Step 4:</span>
[root<span class="hljs-property">@vm</span> automaketest]<span class="hljs-comment"># autoconf</span>

<span class="hljs-comment"># Step 5:</span>
[root<span class="hljs-property">@vm</span> automaketest]<span class="hljs-comment"># autoheader</span>

<span class="hljs-comment"># Step 6:</span>
[root<span class="hljs-property">@vm</span> automaketest]<span class="hljs-comment"># cat Makefile.am </span>
bin_PROGRAMS=main
main_SOURCES=main.c hello.c

<span class="hljs-comment"># Step 7:</span>
[root<span class="hljs-property">@vm</span> automaketest]<span class="hljs-comment"># touch NEWS README AUTHORS ChangeLog</span>

<span class="hljs-comment"># Step 8:</span>
[root<span class="hljs-property">@vm</span> automaketest]<span class="hljs-comment"># automake -a</span>
configure.<span class="hljs-attribute">in</span>:<span class="hljs-number">6</span>: installing <span class="hljs-string">'./install-sh'</span>
configure.<span class="hljs-attribute">in</span>:<span class="hljs-number">6</span>: installing <span class="hljs-string">'./missing'</span>
Makefile.<span class="hljs-attribute">am</span>: installing <span class="hljs-string">'./INSTALL'</span>
Makefile.<span class="hljs-attribute">am</span>: installing <span class="hljs-string">'./COPYING'</span> using GNU General Public License v3 file
Makefile.<span class="hljs-attribute">am</span>:     Consider adding the COPYING file to the version control system
Makefile.<span class="hljs-attribute">am</span>:     <span class="hljs-keyword">for</span> your code, to avoid questions about which license your project uses.
Makefile.<span class="hljs-attribute">am</span>: installing <span class="hljs-string">'./depcomp'</span>

<span class="hljs-comment"># Step 9:</span>
[root<span class="hljs-property">@BC</span>-VM-edce4ac67d304079868c0bb265337bd4 automaketest]<span class="hljs-comment"># ./configure </span>
checking <span class="hljs-keyword">for</span> a BSD-compatible install... /usr/bin/install -c
checking whether build environment <span class="hljs-keyword">is</span> sane... <span class="hljs-literal">yes</span>
checking <span class="hljs-keyword">for</span> a thread-safe mkdir -p... /bin/mkdir -p
checking <span class="hljs-keyword">for</span> gawk... gawk
checking whether make sets $(MAKE)... <span class="hljs-literal">yes</span>
checking <span class="hljs-keyword">for</span> gcc... gcc
checking <span class="hljs-keyword">for</span> C compiler <span class="hljs-reserved">default</span> output file name... a.out
checking whether the C compiler works... <span class="hljs-literal">yes</span>
checking whether we are cross compiling... <span class="hljs-literal">no</span>
checking <span class="hljs-keyword">for</span> suffix <span class="hljs-keyword">of</span> executables... 
checking <span class="hljs-keyword">for</span> suffix <span class="hljs-keyword">of</span> object files... o
checking whether we are using the GNU C compiler... <span class="hljs-literal">yes</span>
checking whether gcc accepts -g... <span class="hljs-literal">yes</span>
checking <span class="hljs-keyword">for</span> gcc option to accept ISO C89... none needed
checking <span class="hljs-keyword">for</span> style <span class="hljs-keyword">of</span> include used <span class="hljs-keyword">by</span> make... GNU
checking dependency style <span class="hljs-keyword">of</span> gcc... gcc3
<span class="hljs-attribute">configure</span>: creating ./config.status
config.<span class="hljs-attribute">status</span>: creating Makefile
config.<span class="hljs-attribute">status</span>: creating config.h
config.<span class="hljs-attribute">status</span>: executing depfiles commands</code><ul style="display: block;" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li><li>8</li><li>9</li><li>10</li><li>11</li><li>12</li><li>13</li><li>14</li><li>15</li><li>16</li><li>17</li><li>18</li><li>19</li><li>20</li><li>21</li><li>22</li><li>23</li><li>24</li><li>25</li><li>26</li><li>27</li><li>28</li><li>29</li><li>30</li><li>31</li><li>32</li><li>33</li><li>34</li><li>35</li><li>36</li><li>37</li><li>38</li><li>39</li><li>40</li><li>41</li><li>42</li><li>43</li><li>44</li><li>45</li><li>46</li><li>47</li><li>48</li><li>49</li><li>50</li><li>51</li><li>52</li><li>53</li><li>54</li><li>55</li><li>56</li><li>57</li><li>58</li><li>59</li><li>60</li><li>61</li><li>62</li><li>63</li><li>64</li><li>65</li><li>66</li><li>67</li><li>68</li><li>69</li><li>70</li><li>71</li><li>72</li><li>73</li><li>74</li><li>75</li><li>76</li><li>77</li><li>78</li></ul>

这样Makefile就生成好了，看一下当前目录发现已经这么多文件了！如果想清理一下怎么办呢？其实Automake早为我们想好了，它生成的Makefile功能很多：
+ make：编译源代码，生成目标文件
+ make clean：清理之前make产生的临时文件
+ make install：将编译好的可执行文件安装到系统目录，一般为/usr/local/bin
+ make dist：生成软件发布包，将可执行文件及相关文件打包成”PACKAGE-VERSION.tar.gz”的tarball。其中PACKAGE和VERSION可以在configure.in中通过AM_INIT_AUTOMAKE(PACKAGE, VERSION)定义。对于我们的例子，执行后会生成main-1.0.tar.gz
+ make distcheck：查看发布包是否正确，解压开执行configure和make来确认
+ make distclean：不仅将make产生的文件，同时将configure生成的文件也都删除，包括Makefile

<code class="language-bash hljs  has-numbering">[root@vm automaketest]<span class="hljs-comment"># make dist</span>
{ test ! <span class="hljs-operator">-d</span> <span class="hljs-string">"main-1.0"</span> || { find <span class="hljs-string">"main-1.0"</span> -type d ! -perm -<span class="hljs-number">200</span> -exec chmod u+w {} <span class="hljs-string">';'</span> && rm -fr <span class="hljs-string">"main-1.0"</span>; }; }
test <span class="hljs-operator">-d</span> <span class="hljs-string">"main-1.0"</span> || mkdir <span class="hljs-string">"main-1.0"</span>
test -n <span class="hljs-string">""</span> \
    || find <span class="hljs-string">"main-1.0"</span> -type d ! -perm -<span class="hljs-number">755</span> \
        -exec chmod u+rwx,go+rx {} \; -o \
      ! -type d ! -perm -<span class="hljs-number">444</span> -links <span class="hljs-number">1</span> -exec chmod a+r {} \; -o \
      ! -type d ! -perm -<span class="hljs-number">400</span> -exec chmod a+r {} \; -o \
      ! -type d ! -perm -<span class="hljs-number">444</span> -exec /bin/sh /root/Temp/automaketest/install-sh -c -m a+r {} {} \; \
    || chmod -R a+r <span class="hljs-string">"main-1.0"</span>
tardir=main-<span class="hljs-number">1.0</span> && /bin/sh /root/Temp/automaketest/missing --run tar chof - <span class="hljs-string">"<span class="hljs-variable">$tardir</span>"</span> | GZIP=--best gzip -c >main-<span class="hljs-number">1.0</span>.tar.gz
{ test ! <span class="hljs-operator">-d</span> <span class="hljs-string">"main-1.0"</span> || { find <span class="hljs-string">"main-1.0"</span> -type d ! -perm -<span class="hljs-number">200</span> -exec chmod u+w {} <span class="hljs-string">';'</span> && rm -fr <span class="hljs-string">"main-1.0"</span>; }; }


[root@vm automaketest]<span class="hljs-comment"># tree -L 1</span>
.
├── aclocal.m4
├── AUTHORS
├── autom4te.cache
├── autoscan.log
├── ChangeLog
├── config.h
├── config.h.in
├── config.log
├── config.status
├── configure
├── configure.in
├── COPYING -> /usr/share/automake-<span class="hljs-number">1.11</span>/COPYING
├── depcomp -> /usr/share/automake-<span class="hljs-number">1.11</span>/depcomp
├── hello.c
├── hello.h
├── INSTALL -> /usr/share/automake-<span class="hljs-number">1.11</span>/INSTALL
├── install-sh -> /usr/share/automake-<span class="hljs-number">1.11</span>/install-sh
├── main.c
├── main-<span class="hljs-number">1.0</span>.tar.gz
├── Makefile
├── Makefile.am
├── Makefile.in
├── missing -> /usr/share/automake-<span class="hljs-number">1.11</span>/missing
├── NEWS
├── README
└── stamp-h1

<span class="hljs-number">1</span> directory, <span class="hljs-number">24</span> files

[root@vm automaketest]<span class="hljs-comment"># make distclean</span>
test -z <span class="hljs-string">"main"</span> || rm <span class="hljs-operator">-f</span> main
rm <span class="hljs-operator">-f</span> *.o
rm <span class="hljs-operator">-f</span> *.tab.c
test -z <span class="hljs-string">""</span> || rm <span class="hljs-operator">-f</span> 
test . = <span class="hljs-string">"."</span> || test -z <span class="hljs-string">""</span> || rm <span class="hljs-operator">-f</span> 
rm <span class="hljs-operator">-f</span> config.h stamp-h1
rm <span class="hljs-operator">-f</span> TAGS ID GTAGS GRTAGS GSYMS GPATH tags
rm <span class="hljs-operator">-f</span> config.status config.cache config.log configure.lineno config.status.lineno
rm -rf ./.deps
rm <span class="hljs-operator">-f</span> Makefile</code><ul style="display: block;" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li><li>8</li><li>9</li><li>10</li><li>11</li><li>12</li><li>13</li><li>14</li><li>15</li><li>16</li><li>17</li><li>18</li><li>19</li><li>20</li><li>21</li><li>22</li><li>23</li><li>24</li><li>25</li><li>26</li><li>27</li><li>28</li><li>29</li><li>30</li><li>31</li><li>32</li><li>33</li><li>34</li><li>35</li><li>36</li><li>37</li><li>38</li><li>39</li><li>40</li><li>41</li><li>42</li><li>43</li><li>44</li><li>45</li><li>46</li><li>47</li><li>48</li><li>49</li><li>50</li><li>51</li><li>52</li><li>53</li><li>54</li><li>55</li><li>56</li></ul>

测试一下，看看Automake生成的Makefile是否能正常工作。

<code class="language-bash hljs  has-numbering">[root@vm automaketest]<span class="hljs-comment"># make</span>
make  all-am
make[<span class="hljs-number">1</span>]: Entering directory <span class="hljs-string">'/root/Temp/automaketest'</span>
gcc -DHAVE_CONFIG_H -I.     -g -O2 -MT main.o -MD -MP -MF .deps/main.Tpo -c -o main.o main.c
mv <span class="hljs-operator">-f</span> .deps/main.Tpo .deps/main.Po
gcc -DHAVE_CONFIG_H -I.     -g -O2 -MT hello.o -MD -MP -MF .deps/hello.Tpo -c -o hello.o hello.c
mv <span class="hljs-operator">-f</span> .deps/hello.Tpo .deps/hello.Po
gcc  -g -O2   -o main main.o hello.o  
make[<span class="hljs-number">1</span>]: Leaving directory <span class="hljs-string">'/root/Temp/automaketest'</span>

[root@vm automaketest]<span class="hljs-comment"># ./main </span>
Hello, Make!</code><ul style="display: block;" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li><li>8</li><li>9</li><li>10</li><li>11</li><li>12</li></ul>

3.2 CMake

前面我们已经见识了Automake的强大和复杂。现在我们重新用CMake生成Makefile，Automake中的9步被压缩到了只需要2步！

编写CMakeLists.txt
执行cmake .

3.2.1 CMakeLists.txt

对于我们示例中这种简单的项目，CMakeLists.txt简单得不能再简单了。指定好项目名称和最终生成的可执行文件名称后，就完成了！

<code class="language-CMake hljs vala has-numbering"><span class="hljs-preprocessor"># CMake 最低版本号要求</span>
cmake_minimum_required (VERSION <span class="hljs-number">2.8</span>)

<span class="hljs-preprocessor"># 项目信息</span>
project (main)

<span class="hljs-preprocessor"># 查找当前目录下的所有源文件</span>
<span class="hljs-preprocessor"># 并将名称保存到 DIR_SRCS 变量</span>
aux_source_directory(. DIR_SRCS)

<span class="hljs-preprocessor"># 指定生成目标</span>
add_executable(main ${DIR_SRCS})</code><ul style="display: block;" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li><li>8</li><li>9</li><li>10</li><li>11</li><li>12</li></ul>

3.2.2 cmake

现在执行cmake .就能得到一个CMake为我们自动生成的Makefile。这个Makefile比我们手写的要复杂得多，这里就不深入分析了。除了Makefile外，CMake还产生了一些缓存文件和临时文件，目前还不清楚具体是做什么的。

<code class="language-bash hljs  has-numbering">[root@vm cmaketest]<span class="hljs-comment"># cmake .</span>
-- The C compiler identification is GNU <span class="hljs-number">4.4</span>.<span class="hljs-number">7</span>
-- The CXX compiler identification is GNU <span class="hljs-number">4.4</span>.<span class="hljs-number">7</span>
-- Check <span class="hljs-keyword">for</span> working C compiler: /usr/bin/cc
-- Check <span class="hljs-keyword">for</span> working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - <span class="hljs-keyword">done</span>
-- Check <span class="hljs-keyword">for</span> working CXX compiler: /usr/bin/c++
-- Check <span class="hljs-keyword">for</span> working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - <span class="hljs-keyword">done</span>
-- Configuring <span class="hljs-keyword">done</span>
-- Generating <span class="hljs-keyword">done</span>
-- Build files have been written to: /root/Temp/cmaketest

[root@vm cmaketest]<span class="hljs-comment"># tree -L 1</span>
.
├── CMakeCache.txt
├── CMakeFiles
├── cmake_install.cmake
├── CMakeLists.txt
├── hello.c
├── hello.h
├── main.c
└── Makefile

<span class="hljs-number">1</span> directory, <span class="hljs-number">7</span> files

[root@vm cmaketest]<span class="hljs-comment"># make</span>
Scanning dependencies of target main
[ <span class="hljs-number">50</span>%] Building C object CMakeFiles/main.dir/main.c.o
[<span class="hljs-number">100</span>%] Building C object CMakeFiles/main.dir/hello.c.o
Linking C executable main
[<span class="hljs-number">100</span>%] Built target main</code><ul style="display: block;" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li><li>8</li><li>9</li><li>10</li><li>11</li><li>12</li><li>13</li><li>14</li><li>15</li><li>16</li><li>17</li><li>18</li><li>19</li><li>20</li><li>21</li><li>22</li><li>23</li><li>24</li><li>25</li><li>26</li><li>27</li><li>28</li><li>29</li><li>30</li><li>31</li><li>32</li><li>33</li><li>34</li></ul>

C实战：项目构建Make,Automake,CMake

C实战：项目构建Make,Automake,CMake

1.Make基础

1.1 基本语法

1.2 实现原理

2.Make进阶

2.1 变量

2.2 隐式规则

2.3 模式规则

3.Makefile生成工具

3.1 Automake

3.2 CMake

3.2.1 CMakeLists.txt

3.2.2 cmake

附：参考资料

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