Question

我很难在学习C的Exercise 32中编写难以编译的代码。

我已经从创建者的GitHub repo逐字复制了代码，甚至克隆在新的存储库中。我查看了其他存储库，除了Ubuntu之外，还尝试了我的MacOSX等等。我似乎没有做任何编译。

我使用的是Ubuntu 12.04（见下文）。

这是我的文件结构（注意 - 这是我直接从练习32中包含文件时的文件结构。显然，当我克隆git存储库时，我会获得更多文件。我使用diff来确保我的所有文件文件，包括我的make文件，在我的削减版本中完全类似于git存储库）：

$ pwd
/usr/local/me/code/C/liblcthw


$ ls
bin  LICENSE  Makefile  README.md  src  tests

$ ls tests/
list_tests.c  minunit.h  runtests.sh

$ ls src/lcthw/
dbg.h  list.c  list.h

这是我的make命令。

$ make
cc -g -O2 -Wall -Wextra -Isrc -rdynamic -DNDEBUG  -fPIC   -c -o src/lcthw/list.o src/lcthw/list.c
ar rcs build/liblcthw.a src/lcthw/list.o
ranlib build/liblcthw.a
cc -g -O2 -Wall -Wextra -Isrc -rdynamic -DNDEBUG  build/liblcthw.a    tests/list_tests.c   -o tests/list_tests
tests/list_tests.c: In function ‘main’:
tests/list_tests.c:111:1: warning: parameter ‘argc’ set but not used [-Wunused-but-set-parameter]
/tmp/ccXlNfMl.o: In function `test_create':
/usr/local/me/code/C/liblcthw/tests/list_tests.c:13: undefined reference to `List_create'
/tmp/ccXlNfMl.o: In function `test_destroy':
/usr/local/me/code/C/liblcthw/tests/list_tests.c:22: undefined reference to `List_clear_destroy'
/tmp/ccXlNfMl.o: In function `test_push_pop':
/usr/local/me/code/C/liblcthw/tests/list_tests.c:31: undefined reference to `List_push'
/usr/local/me/code/C/liblcthw/tests/list_tests.c:34: undefined reference to `List_push'
/usr/local/me/code/C/liblcthw/tests/list_tests.c:37: undefined reference to `List_push'
/usr/local/me/code/C/liblcthw/tests/list_tests.c:41: undefined reference to `List_pop'
/usr/local/me/code/C/liblcthw/tests/list_tests.c:44: undefined reference to `List_pop'
/usr/local/me/code/C/liblcthw/tests/list_tests.c:47: undefined reference to `List_pop'
/tmp/ccXlNfMl.o: In function `test_shift':
/usr/local/me/code/C/liblcthw/tests/list_tests.c:56: undefined reference to `List_shift'
/usr/local/me/code/C/liblcthw/tests/list_tests.c:59: undefined reference to `List_shift'
/usr/local/me/code/C/liblcthw/tests/list_tests.c:62: undefined reference to `List_shift'
/tmp/ccXlNfMl.o: In function `test_remove':
/usr/local/me/code/C/liblcthw/tests/list_tests.c:74: undefined reference to `List_remove'
/tmp/ccXlNfMl.o: In function `test_unshift':
/usr/local/me/code/C/liblcthw/tests/list_tests.c:86: undefined reference to `List_unshift'
/usr/local/me/code/C/liblcthw/tests/list_tests.c:89: undefined reference to `List_unshift'
collect2: ld returned 1 exit status
make: *** [tests/list_tests] Error 1

我正在使用Ubuntu 12.04

$ lsb_release -a
LSB Version:    core-2.0-amd64:core-2.0-noarch:core-3.0-amd64:core-3.0-noarch:core-3.1-amd64:core-3.1-noarch:core-3.2-amd64:core-3.2-noarch:core-4.0-amd64:core-4.0-noarch:cxx-3.0-amd64:cxx-3.0-noarch:cxx-3.1-amd64:cxx-3.1-noarch:cxx-3.2-amd64:cxx-3.2-noarch:cxx-4.0-amd64:cxx-4.0-noarch:desktop-3.1-amd64:desktop-3.1-noarch:desktop-3.2-amd64:desktop-3.2-noarch:desktop-4.0-amd64:desktop-4.0-noarch:graphics-2.0-amd64:graphics-2.0-noarch:graphics-3.0-amd64:graphics-3.0-noarch:graphics-3.1-amd64:graphics-3.1-noarch:graphics-3.2-amd64:graphics-3.2-noarch:graphics-4.0-amd64:graphics-4.0-noarch:printing-3.2-amd64:printing-3.2-noarch:printing-4.0-amd64:printing-4.0-noarch:qt4-3.1-amd64:qt4-3.1-noarch
Distributor ID: Ubuntu
Description:    Ubuntu 12.04.2 LTS
Release:        12.04
Codename:       precise

Answer 1

从github repo下载的练习32代码是特定于BSD系统（可能是OS X）的平台。具体来说，BSD系统上存在一些成功构建的必需符号，但很可能不存在于（Linux）Ubuntu 12.04系统上。其中包括：

mergesort
heapsort

尽管如此，库和单元测试都可以成功编译，但一个单元测试除外（最终）将需要上述符号。如果对下面显示的makefile中的缺陷稍有改动，那么从tests目录移动单个有问题的测试将允许其他测试在（Linux）SuSE SLES 11系统上进行编译。

下载问题中提到的来源后：

.../liblcthw-master> ll
total 28
drwxr-xr-x 2 mahonri users 4096 May 24 21:30 bin
drwxr-xr-x 2 mahonri users 4096 May 24 21:53 build
-rw-r--r-- 1 mahonri users 1548 May  8  2012 LICENSE
-rw-r--r-- 1 mahonri users 1139 May  8  2012 Makefile
-rw-r--r-- 1 mahonri users 1069 May  8  2012 README.md
drwxr-xr-x 3 mahonri users 4096 May 24 21:52 src
drwxr-xr-x 2 mahonri users 4096 May 24 21:53 tests

可以在Makefile中找到缺陷。以下是Makefile的有缺陷的部分，如下载：

# The Unit Tests
.PHONY: tests
tests: CFLAGS += $(TARGET)
tests: $(TESTS)
       sh ./tests/runtests.sh

一个问题是将$（TARGET）build/liblcthw.a的值放在CFLAGS的末尾并不起作用。这是因为CFLAGS针对的是编译器，而不是链接器。因此，由此产生的测试＆＃39;目标没有与图书馆链接。

另一个问题是至少有一个＆＃39;测试＆＃39;应用程序需要数学库。

要解决这些问题，必须将Makefile修改为类似以下内容：

# The Unit Tests
.PHONY: tests
tests: LDLIBS += -lm -L./build -llcthw
tests: $(TESTS)
       sh ./tests/runtests.sh

构建liblcthw.a，并构建＆＃39;测试＆＃39;应用程序，针对此目录中更新的make运行Makefile：

.../liblcthw-master> ll
total 28
drwxr-xr-x 2 mahonri users 4096 May 24 21:30 bin
drwxr-xr-x 2 mahonri users 4096 May 24 21:53 build
-rw-r--r-- 1 mahonri users 1548 May  8  2012 LICENSE
-rw-r--r-- 1 mahonri users 1139 May  8  2012 Makefile
-rw-r--r-- 1 mahonri users 1069 May  8  2012 README.md
drwxr-xr-x 3 mahonri users 4096 May 24 21:52 src
drwxr-xr-x 2 mahonri users 4096 May 24 21:53 tests
.../liblcthw-master> make
cc -g -O2 -Wall -Wextra -Isrc -rdynamic -DNDEBUG  -fPIC   -c -o src/lcthw/bstree.o src/lcthw/bstree.c
cc -g -O2 -Wall -Wextra -Isrc -rdynamic -DNDEBUG  -fPIC   -c -o src/lcthw/bstrlib.o src/lcthw/bstrlib.c
cc -g -O2 -Wall -Wextra -Isrc -rdynamic -DNDEBUG  -fPIC   -c -o src/lcthw/darray_algos.o src/lcthw/darray_algos.c
src/lcthw/darray_algos.c: In function ‘DArray_heapsort’:
src/lcthw/darray_algos.c:12: warning: implicit declaration of function ‘heapsort’
src/lcthw/darray_algos.c: In function ‘DArray_mergesort’:
src/lcthw/darray_algos.c:17: warning: implicit declaration of function ‘mergesort’
cc -g -O2 -Wall -Wextra -Isrc -rdynamic -DNDEBUG  -fPIC   -c -o src/lcthw/darray.o src/lcthw/darray.c
cc -g -O2 -Wall -Wextra -Isrc -rdynamic -DNDEBUG  -fPIC   -c -o src/lcthw/hashmap_algos.o src/lcthw/hashmap_algos.c
cc -g -O2 -Wall -Wextra -Isrc -rdynamic -DNDEBUG  -fPIC   -c -o src/lcthw/hashmap.o src/lcthw/hashmap.c
cc -g -O2 -Wall -Wextra -Isrc -rdynamic -DNDEBUG  -fPIC   -c -o src/lcthw/list_algos.o src/lcthw/list_algos.c
cc -g -O2 -Wall -Wextra -Isrc -rdynamic -DNDEBUG  -fPIC   -c -o src/lcthw/list.o src/lcthw/list.c
cc -g -O2 -Wall -Wextra -Isrc -rdynamic -DNDEBUG  -fPIC   -c -o src/lcthw/radixmap.o src/lcthw/radixmap.c
cc -g -O2 -Wall -Wextra -Isrc -rdynamic -DNDEBUG  -fPIC   -c -o src/lcthw/ringbuffer.o src/lcthw/ringbuffer.c
cc -g -O2 -Wall -Wextra -Isrc -rdynamic -DNDEBUG  -fPIC   -c -o src/lcthw/sarray.o  src/lcthw/sarray.c
src/lcthw/sarray.c: In function ‘SuffixArray_create’:
src/lcthw/sarray.c:71: warning: implicit declaration of function ‘qsort_r’
cc -g -O2 -Wall -Wextra -Isrc -rdynamic -DNDEBUG  -fPIC   -c -o src/lcthw/stats.o src/lcthw/stats.c
cc -g -O2 -Wall -Wextra -Isrc -rdynamic -DNDEBUG  -fPIC   -c -o src/lcthw/tstree.o src/lcthw/tstree.c
ar rcs build/liblcthw.a src/lcthw/bstree.o src/lcthw/bstrlib.o src/lcthw/darray_algos.o src/lcthw/darray.o src/lcthw/hashmap_algos.o src/lcthw/hashmap.o src/lcthw/list_algos.o src/lcthw/list.o src/lcthw/radixmap.o src/lcthw/ringbuffer.o src/lcthw/sarray.o src/lcthw/stats.o src/lcthw/tstree.o
ranlib build/liblcthw.a
cc -g -O2 -Wall -Wextra -Isrc -rdynamic -DNDEBUG     tests/bstree_tests.c  -L./build -llcthw -o tests/bstree_tests
cc -g -O2 -Wall -Wextra -Isrc -rdynamic -DNDEBUG     tests/bstr_tests.c  -L./build -llcthw -o tests/bstr_tests
cc -g -O2 -Wall -Wextra -Isrc -rdynamic -DNDEBUG     tests/darray_algos_tests.c  -L./build -llcthw -o tests/darray_algos_tests
...

然后，makefile继续运行测试可执行文件：

sh ./tests/runtests.sh
Running unit tests:
----
RUNNING: ./tests/bstree_tests
ALL TESTS PASSED
Tests run: 5
tests/bstree_tests PASS
tests/bstr_tests PASS
----
RUNNING: ./tests/darray_tests
ALL TESTS PASSED
Tests run: 8
tests/darray_tests PASS
----
RUNNING: ./tests/hashmap_algos_tests
ALL TESTS PASSED
Tests run: 4
tests/hashmap_algos_tests PASS
----
RUNNING: ./tests/hashmap_tests
ALL TESTS PASSED
Tests run: 5
tests/hashmap_tests PASS
----
RUNNING: ./tests/list_algos_tests
ALL TESTS PASSED
Tests run: 2
tests/list_algos_tests PASS
----
RUNNING: ./tests/list_tests
ALL TESTS PASSED
Tests run: 6
tests/list_tests PASS
----
RUNNING: ./tests/queue_tests
ALL TESTS PASSED
Tests run: 3
tests/queue_tests PASS
----
RUNNING: ./tests/radixmap_tests
ALL TESTS PASSED
Tests run: 1
tests/radixmap_tests PASS
----
RUNNING: ./tests/ringbuffer_tests
ALL TESTS PASSED
Tests run: 3
tests/ringbuffer_tests PASS
----
RUNNING: ./tests/sarray_tests
./tests/runtests.sh: line 3:  1033 Segmentation fault      $VALGRIND ./$i 2>>  tests/tests.log
ERROR in test tests/sarray_tests: here's tests/tests.log
------
DEBUG tests/ringbuffer_tests.c:60: ----- RUNNING: ./tests/ringbuffer_tests
DEBUG tests/ringbuffer_tests.c:53: 
----- test_create
DEBUG tests/ringbuffer_tests.c:54: 
----- test_read_write
DEBUG tests/ringbuffer_tests.c:55: 
----- test_destroy
DEBUG tests/sarray_tests.c:46: ----- RUNNING: ./tests/sarray_tests
DEBUG tests/sarray_tests.c:39: 
----- test_create
make: *** [tests] Error 1

注意：同样的缺陷似乎不会影响OS X 8构建（这对我自己来说是一个难题）。必须在OS X 8版本的构建中修复一个单独的缺陷。具体而言，list_algos.c中的以下行：

...

inline List *List_merge(List *left, List *right, List_compare cmp)
{
   List *result = List_create();
...

内联函数需要函数原型。更改为以下内容：

...

extern List *List_merge(List *left, List *right, List_compare cmp);
inline List *List_merge(List *left, List *right, List_compare cmp)
{
   List *result = List_create();
...

经过一次修改后，OS X版本能够成功make。

C编译错误 - 艰难地学习C（Ex 32）

1 个答案: