{"id":106,"date":"2026-09-23T19:39:34","date_gmt":"2026-09-23T11:39:34","guid":{"rendered":"https:\/\/decagrammaton.xyz\/?p=106"},"modified":"2026-09-18T19:40:01","modified_gmt":"2026-09-18T11:40:01","slug":"015-c%e8%af%ad%e8%a8%80%e5%b8%b8%e8%a7%81%e5%9d%91%e4%b8%8e%e8%b0%83%e8%af%95","status":"publish","type":"post","link":"https:\/\/decagrammaton.xyz\/?p=106","title":{"rendered":"015-C\u8bed\u8a00\u5e38\u89c1\u5751\u4e0e\u8c03\u8bd5"},"content":{"rendered":"\n
\n\n\n\n

\u524d\u9762\u5df2\u7ecf\u5b66\u4e60\u4e86\uff1a<\/p>\n\n\n\n

\u53d8\u91cf\n\u8f93\u5165\u8f93\u51fa\n\u5224\u65ad\n\u5faa\u73af\n\u51fd\u6570\n\u6570\u7ec4\n\u5b57\u7b26\u4e32\n\u6307\u9488\n\u7ed3\u6784\u4f53\n\u52a8\u6001\u5185\u5b58\n\u6587\u4ef6\n\u5934\u6587\u4ef6\n\u591a\u6587\u4ef6\nMakefile<\/code><\/pre>\n\n\n\n
\u5b66\u4e60\u5230\u8fd9\u91cc\uff0c\u4ee3\u7801\u5f00\u59cb\u53d8\u590d\u6742\u3002<\/p>\n\n\n\n
\u4e8e\u662f\u4f1a\u7ecf\u5e38\u9047\u5230\uff1a<\/p>\n\n\n\n
\u7f16\u8bd1\u62a5\u9519\n\u94fe\u63a5\u62a5\u9519\n\u7a0b\u5e8f\u5d29\u6e83\n\u8f93\u51fa\u4e0d\u5bf9\n\u6570\u636e\u83ab\u540d\u5176\u5999\u6539\u53d8<\/code><\/pre>\n\n\n\n
\u8fd9\u65f6\u5019\u6700\u91cd\u8981\u7684\u4e0d\u662f\uff1a<\/p>\n\n\n\n
\u201c\u591a\u8bd5\u51e0\u6b21\u201d<\/code><\/pre>\n\n\n\n
\u800c\u662f\u5b66\u4f1a\uff1a<\/p>\n\n\n\n
\u5b9a\u4f4d\u95ee\u9898\u3002<\/strong><\/p>\n\n\n\n
\n\n\n\n
\u4e00\u3001\u4ec0\u4e48\u662f Bug<\/h1>\n\n\n\n
Bug \u5c31\u662f\u7a0b\u5e8f\u4e2d\u7684\u9519\u8bef\u3002<\/p>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> a =<\/span> 10<\/span>;<\/span><\/span>\n<\/a>int<\/span> b =<\/span> 0<\/span>;<\/span><\/span>\n<\/a><\/span>\n<\/a>printf(<\/span>\"<\/span>%d\\n<\/span>\"<\/span>,<\/span> a \/<\/span> b);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u7a0b\u5e8f\u51fa\u73b0\u9519\u8bef\u3002<\/p>\n\n\n\n
\u53c8\u6bd4\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> arr[<\/span>5<\/span>];<\/span><\/span>\n<\/a><\/span>\n<\/a>arr[<\/span>10<\/span>]<\/span> =<\/span> 100<\/span>;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4e5f\u662f\u9519\u8bef\u3002<\/p>\n\n\n\n
\u5e38\u89c1\u9519\u8bef\u53ef\u4ee5\u5206\u6210\uff1a<\/p>\n\n\n\n
\u7f16\u8bd1\u9519\u8bef\n\u94fe\u63a5\u9519\u8bef\n\u8fd0\u884c\u65f6\u9519\u8bef\n\u903b\u8f91\u9519\u8bef<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u4e8c\u3001\u7f16\u8bd1\u9519\u8bef<\/h1>\n\n\n\n
\u7f16\u8bd1\u5668\u65e0\u6cd5\u628a .c<\/code> \u4ee3\u7801\u7f16\u8bd1\u6210\u76ee\u6807\u6587\u4ef6\u3002<\/p>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>#include <\/span><stdio.h><\/span><\/span>\n<\/a><\/span>\n<\/a>int<\/span> main()<\/span> {<\/span><\/span>\n<\/a>    printf(<\/span>\"Hello<\/span>\\n<\/span>\"<\/span><\/span>\n<\/a>    return<\/span> 0<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5c11\u4e86\uff1a<\/p>\n\n\n\n
)<\/code><\/pre>\n\n\n\n
\u53ef\u80fd\u51fa\u73b0\uff1a<\/p>\n\n\n\n
error: expected ')' before 'return'<\/code><\/pre>\n\n\n\n
\u8fd9\u7c7b\u95ee\u9898\u5c5e\u4e8e\uff1a<\/p>\n\n\n\n
\u7f16\u8bd1\u9519\u8bef\u3002<\/strong><\/p>\n\n\n\n
\n\n\n\n
\u4e09\u3001\u5e38\u89c1\u7f16\u8bd1\u9519\u8bef<\/h1>\n\n\n\n
1. \u5c11\u5206\u53f7<\/h2>\n\n\n\n
\u9519\u8bef\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> a =<\/span> 10<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u6b63\u786e\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> a =<\/span> 10<\/span>;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
2. \u62ec\u53f7\u4e0d\u5339\u914d<\/h2>\n\n\n\n
\u9519\u8bef\uff1a<\/p>\n\n\n\n
<\/a>if<\/span> (<\/span>a ><\/span> 10<\/span> {<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u6b63\u786e\uff1a<\/p>\n\n\n\n
<\/a>if<\/span> (<\/span>a ><\/span> 10<\/span>)<\/span> {<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
3. \u5927\u62ec\u53f7\u4e0d\u5339\u914d<\/h2>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> main()<\/span> {<\/span><\/span>\n<\/a><\/span>\n<\/a>    if<\/span> (<\/span>a ><\/span> 10<\/span>)<\/span> {<\/span><\/span>\n<\/a>        printf(<\/span>\"A<\/span>\\n<\/span>\"<\/span>);<\/span><\/span>\n<\/a><\/span>\n<\/a>    return<\/span> 0<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5c11\u4e00\u4e2a\uff1a<\/p>\n\n\n\n
}<\/code><\/pre>\n\n\n\n
\n\n\n\n
4. \u62fc\u5199\u9519\u8bef<\/h2>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>pritnf(<\/span>\"Hello\"<\/span>);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u6b63\u786e\uff1a<\/p>\n\n\n\n
<\/a>printf(<\/span>\"Hello\"<\/span>);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
5. \u5fd8\u8bb0\u5934\u6587\u4ef6<\/h2>\n\n\n\n
\u4f8b\u5982\u4f7f\u7528\uff1a<\/p>\n\n\n\n
<\/a>malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5374\u6ca1\u6709\uff1a<\/p>\n\n\n\n
<\/a>#include <\/span><stdlib.h><\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5e94\u8be5\u8865\u4e0a\u3002<\/p>\n\n\n\n
\n\n\n\n
\u56db\u3001\u8b66\u544a\u4e0d\u662f\u9519\u8bef<\/h1>\n\n\n\n
\u7f16\u8bd1\u65f6\u53ef\u80fd\u51fa\u73b0\uff1a<\/p>\n\n\n\n
warning<\/code><\/pre>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> a =<\/span> 10.5<\/span>;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u53ef\u80fd\u51fa\u73b0\u7c7b\u578b\u8f6c\u6362\u76f8\u5173\u8b66\u544a\u3002<\/p>\n\n\n\n
\u7a0b\u5e8f\u4e5f\u8bb8\u4ecd\u7136\u53ef\u4ee5\u751f\u6210\u3002<\/p>\n\n\n\n
\u4f46\u662f\uff1a<\/p>\n\n\n\n
\u4e0d\u8981\u4e60\u60ef\u6027\u5ffd\u7565 warning\u3002<\/strong><\/p>\n\n\n\n
\u63a8\u8350\u4f7f\u7528\uff1a<\/p>\n\n\n\n
<\/a>gcc<\/span> -Wall<\/span> -Wextra<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>gcc<\/span> -Wall<\/span> -Wextra<\/span> main.c -o<\/span> main<\/span><\/code><\/pre><\/div>\n\n\n\n
\u8fd9\u6837\u53ef\u4ee5\u8ba9\u7f16\u8bd1\u5668\u544a\u8bc9\u4f60\u66f4\u591a\u6f5c\u5728\u95ee\u9898\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e94\u3001\u94fe\u63a5\u9519\u8bef<\/h1>\n\n\n\n
\u6709\u65f6\u5019\uff1a<\/p>\n\n\n\n
.c<\/code><\/pre>\n\n\n\n
\u53ef\u4ee5\u6210\u529f\u7f16\u8bd1\u3002<\/p>\n\n\n\n
\u4f46\u662f\u6700\u540e\u751f\u6210\u7a0b\u5e8f\u65f6\u5931\u8d25\u3002<\/p>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>#include <\/span>\"hello.h\"<\/span><\/span>\n<\/a><\/span>\n<\/a>int<\/span> main()<\/span> {<\/span><\/span>\n<\/a>    hello();<\/span><\/span>\n<\/a>    return<\/span> 0<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
hello.h<\/code>\uff1a<\/p>\n\n\n\n
<\/a>void<\/span> hello();<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4f46\u662f\u4f60\u6ca1\u6709\u7f16\u8bd1\uff1a<\/p>\n\n\n\n
hello.c<\/code><\/pre>\n\n\n\n
\u6267\u884c\uff1a<\/p>\n\n\n\n
<\/a>gcc<\/span> main.c -o<\/span> main<\/span><\/code><\/pre><\/div>\n\n\n\n
\u53ef\u80fd\u51fa\u73b0\uff1a<\/p>\n\n\n\n
undefined reference to `hello`<\/code><\/pre>\n\n\n\n
\u8fd9\u5c5e\u4e8e\uff1a<\/p>\n\n\n\n
\u94fe\u63a5\u9519\u8bef\u3002<\/strong><\/p>\n\n\n\n
\n\n\n\n
\u516d\u3001\u7f16\u8bd1\u9519\u8bef\u548c\u94fe\u63a5\u9519\u8bef<\/h1>\n\n\n\n
\u53ef\u4ee5\u8fd9\u6837\u533a\u5206\uff1a<\/p>\n\n\n\n
\u7f16\u8bd1\u9519\u8bef\n\u2193\n\u4ee3\u7801\u8bed\u6cd5\/\u7c7b\u578b\u7b49\u6709\u95ee\u9898\n\u2193\n.c \u2192 .o \u5931\u8d25\n\n\u94fe\u63a5\u9519\u8bef\n\u2193\n\u5404\u4e2a .o \u4e4b\u95f4\u627e\u4e0d\u5230\u9700\u8981\u7684\u4e1c\u897f\n\u2193\n.o \u2192 \u53ef\u6267\u884c\u6587\u4ef6\u5931\u8d25<\/code><\/pre>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
main.c\n\u2193\n\u7f16\u8bd1\n\u2193\nmain.o<\/code><\/pre>\n\n\n\n
\u6210\u529f\u3002<\/p>\n\n\n\n
\u4f46\u662f\uff1a<\/p>\n\n\n\n
main.o\n\u2193\n\u5bfb\u627e hello()\n\u2193\n\u627e\u4e0d\u5230\u5b9e\u73b0\n\u2193\n\u94fe\u63a5\u5931\u8d25<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u4e03\u3001\u8fd0\u884c\u65f6\u9519\u8bef<\/h1>\n\n\n\n
\u7a0b\u5e8f\u5df2\u7ecf\u7f16\u8bd1\u6210\u529f\uff1a<\/p>\n\n\n\n
gcc\n\u2193\n\u6210\u529f<\/code><\/pre>\n\n\n\n
\u4f46\u662f\u8fd0\u884c\u4ee5\u540e\u5d29\u6e83\u3002<\/p>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> NULL;<\/span><\/span>\n<\/a><\/span>\n<\/a>printf(<\/span>\"<\/span>%d\\n<\/span>\"<\/span>,<\/span> *<\/span>p);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u7a0b\u5e8f\u53ef\u80fd\u76f4\u63a5\uff1a<\/p>\n\n\n\n
\u5d29\u6e83<\/code><\/pre>\n\n\n\n
\u8fd9\u5c31\u662f\uff1a<\/p>\n\n\n\n
\u8fd0\u884c\u65f6\u9519\u8bef\u3002<\/strong><\/p>\n\n\n\n
\n\n\n\n
\u516b\u3001\u6bb5\u9519\u8bef<\/h1>\n\n\n\n
Linux \u4e0b\u7ecf\u5e38\u770b\u5230\uff1a<\/p>\n\n\n\n
Segmentation fault<\/code><\/pre>\n\n\n\n
\u7b80\u79f0\uff1a<\/p>\n\n\n\n
Segfault<\/code><\/pre>\n\n\n\n
Windows \u73af\u5883\u4e0b\u53ef\u80fd\u8868\u73b0\u4e3a\uff1a<\/p>\n\n\n\n
\u7a0b\u5e8f\u5d29\u6e83\n\u8bbf\u95ee\u51b2\u7a81<\/code><\/pre>\n\n\n\n
\u5e38\u89c1\u539f\u56e0\uff1a<\/p>\n\n\n\n
\u7a7a\u6307\u9488\u89e3\u5f15\u7528\n\u91ce\u6307\u9488\n\u6570\u7ec4\u8d8a\u754c\nuse-after-free\n\u5199\u5165\u4e0d\u53ef\u8bbf\u95ee\u5185\u5b58<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u4e5d\u3001\u7a7a\u6307\u9488<\/h1>\n\n\n\n
\u9519\u8bef\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> NULL;<\/span><\/span>\n<\/a><\/span>\n<\/a>*<\/span>p =<\/span> 100<\/span>;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u95ee\u9898\uff1a<\/p>\n\n\n\n
p\n\u2193\nNULL\n\u2193\n\u6ca1\u6709\u6709\u6548\u5bf9\u8c61<\/code><\/pre>\n\n\n\n
\u5374\u8fdb\u884c\uff1a<\/p>\n\n\n\n
<\/a>*<\/span>p =<\/span> 100<\/span>;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8fd9\u662f\u975e\u6cd5\u8bbf\u95ee\u3002<\/p>\n\n\n\n
\u6b63\u786e\u601d\u8def\uff1a<\/p>\n\n\n\n
<\/a>if<\/span> (<\/span>p !=<\/span> NULL)<\/span> {<\/span><\/span>\n<\/a>    *<\/span>p =<\/span> 100<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
\u5341\u3001\u6570\u7ec4\u8d8a\u754c<\/h1>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> arr[<\/span>5<\/span>];<\/span><\/span>\n<\/a><\/span>\n<\/a>arr[<\/span>5<\/span>]<\/span> =<\/span> 100<\/span>;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5408\u6cd5\u4e0b\u6807\uff1a<\/p>\n\n\n\n
0\n1\n2\n3\n4<\/code><\/pre>\n\n\n\n
arr[5]<\/code> \u5df2\u7ecf\u8d8a\u754c\u3002<\/p>\n\n\n\n
\u53ef\u4ee5\u8bb0\uff1a<\/p>\n\n\n\n
int arr[5]\n\u2193\n5 \u4e2a\u5143\u7d20\n\u2193\n\u4e0b\u6807 0 ~ 4<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u5341\u4e00\u3001\u6570\u7ec4\u8d8a\u754c\u4e3a\u4ec0\u4e48\u5371\u9669<\/h1>\n\n\n\n
\u6700\u9ebb\u70e6\u7684\u5730\u65b9\u662f\uff1a<\/p>\n\n\n\n
\u8d8a\u754c\u4e0d\u4e00\u5b9a\u9a6c\u4e0a\u5d29\u6e83\u3002<\/strong><\/p>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> arr[<\/span>5<\/span>];<\/span><\/span>\n<\/a><\/span>\n<\/a>arr[<\/span>100<\/span>]<\/span> =<\/span> 10<\/span>;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u7a0b\u5e8f\u53ef\u80fd\uff1a<\/p>\n\n\n\n
\u770b\u8d77\u6765\u6ca1\u95ee\u9898<\/code><\/pre>\n\n\n\n
\u4e5f\u53ef\u80fd\uff1a<\/p>\n\n\n\n
\u6570\u636e\u635f\u574f<\/code><\/pre>\n\n\n\n
\u4e5f\u53ef\u80fd\uff1a<\/p>\n\n\n\n
\u76f4\u63a5\u5d29\u6e83<\/code><\/pre>\n\n\n\n
\u6240\u4ee5\uff1a<\/p>\n\n\n\n
\u7a0b\u5e8f\u6ca1\u6709\u5d29\u6e83 \u2260 \u4ee3\u7801\u6b63\u786e\u3002<\/strong><\/p>\n\n\n\n
\n\n\n\n
\u5341\u4e8c\u3001\u5b57\u7b26\u4e32\u6700\u5bb9\u6613\u8d8a\u754c<\/h1>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>char<\/span> name[<\/span>5<\/span>];<\/span><\/span>\n<\/a><\/span>\n<\/a>strcpy(<\/span>name,<\/span> \"Alice\"<\/span>);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\"Alice\"<\/code> \u5b9e\u9645\u9700\u8981\uff1a<\/p>\n\n\n\n
A\nl\ni\nc\ne\n\\0<\/code><\/pre>\n\n\n\n
\u4e00\u5171\uff1a<\/p>\n\n\n\n
6 \u4e2a char<\/code><\/pre>\n\n\n\n
\u800c\uff1a<\/p>\n\n\n\n
<\/a>char<\/span> name[<\/span>5<\/span>];<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u53ea\u6709 5 \u4e2a\u4f4d\u7f6e\u3002<\/p>\n\n\n\n
\u56e0\u6b64\u53d1\u751f\u8d8a\u754c\u3002<\/p>\n\n\n\n
\u5e94\u8be5\uff1a<\/p>\n\n\n\n
<\/a>char<\/span> name[<\/span>6<\/span>];<\/span><\/span>\n<\/a><\/span>\n<\/a>strcpy(<\/span>name,<\/span> \"Alice\"<\/span>);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u6216\u8005\u6839\u636e\u5b9e\u9645\u9700\u6c42\u9884\u7559\u8db3\u591f\u7a7a\u95f4\u3002<\/p>\n\n\n\n
\n\n\n\n
\u5341\u4e09\u3001\u5b57\u7b26\u4e32\u7684 \\0<\/h1>\n\n\n\n
\u8fd9\u662f C \u5b57\u7b26\u4e32\u6700\u5e38\u89c1\u7684\u5751\u4e4b\u4e00\u3002<\/p>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>char<\/span> str[<\/span>6<\/span>]<\/span> =<\/span> \"Hello\"<\/span>;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5b9e\u9645\u4e0a\uff1a<\/p>\n\n\n\n
H\ne\nl\nl\no\n\\0<\/code><\/pre>\n\n\n\n
\u6240\u4ee5\uff1a<\/p>\n\n\n\n
\"Hello\"<\/code><\/pre>\n\n\n\n
\u9700\u8981\uff1a<\/p>\n\n\n\n
6 \u4e2a char<\/code><\/pre>\n\n\n\n
\u4e0d\u662f 5 \u4e2a\u3002<\/p>\n\n\n\n
\n\n\n\n
\u5341\u56db\u3001scanf \u7684\u5751<\/h1>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>char<\/span> name[<\/span>20<\/span>];<\/span><\/span>\n<\/a><\/span>\n<\/a>scanf(<\/span>\"<\/span>%s<\/span>\"<\/span>,<\/span> name);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5982\u679c\u8f93\u5165\u7279\u522b\u957f\uff1a<\/p>\n\n\n\n
abcdefghijklmnopqrstuvwxyz...<\/code><\/pre>\n\n\n\n
\u53ef\u80fd\u5bfc\u81f4\uff1a<\/p>\n\n\n\n
\u7f13\u51b2\u533a\u6ea2\u51fa\u3002<\/strong><\/p>\n\n\n\n
\u66f4\u5b89\u5168\u7684\u57fa\u672c\u5199\u6cd5\uff1a<\/p>\n\n\n\n
<\/a>scanf(<\/span>\"<\/span>%19s<\/span>\"<\/span>,<\/span> name);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u56e0\u4e3a\u9700\u8981\u7559\u4e00\u4e2a\u4f4d\u7f6e\u7ed9\uff1a<\/p>\n\n\n\n
\\0<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u5341\u4e94\u3001scanf \u548c\u6362\u884c\u95ee\u9898<\/h1>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> age;<\/span><\/span>\n<\/a><\/span>\n<\/a>scanf(<\/span>\"<\/span>%d<\/span>\"<\/span>,<\/span> &<\/span>age);<\/span><\/span>\n<\/a><\/span>\n<\/a>char<\/span> name[<\/span>50<\/span>];<\/span><\/span>\n<\/a><\/span>\n<\/a>fgets(<\/span>name,<\/span> sizeof<\/span>(<\/span>name),<\/span> stdin);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u53ef\u80fd\u53d1\u73b0\uff1a<\/p>\n\n\n\n
fgets()<\/code><\/pre>\n\n\n\n
\u76f4\u63a5\u8bfb\u53d6\u4e86\u4e00\u4e2a\u7a7a\u884c\u3002<\/p>\n\n\n\n
\u539f\u56e0\u662f\uff1a<\/p>\n\n\n\n
scanf(\"%d\")<\/code><\/pre>\n\n\n\n
\u8bfb\u53d6\u6570\u5b57\u4ee5\u540e\uff1a<\/p>\n\n\n\n
\\n<\/code><\/pre>\n\n\n\n
\u53ef\u80fd\u8fd8\u7559\u5728\u8f93\u5165\u7f13\u51b2\u533a\u3002<\/p>\n\n\n\n
\u8fd9\u662f\u521d\u5b66\u9636\u6bb5\u975e\u5e38\u5e38\u89c1\u7684\u95ee\u9898\u3002<\/p>\n\n\n\n
\n\n\n\n
\u5341\u516d\u3001\u89e3\u51b3 scanf + fgets<\/h1>\n\n\n\n
\u7b80\u5355\u573a\u666f\u53ef\u4ee5\u4f7f\u7528\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> c;<\/span><\/span>\n<\/a><\/span>\n<\/a>while<\/span> ((<\/span>c =<\/span> getchar())<\/span> !=<\/span> '<\/span>\\n<\/span>'<\/span> &&<\/span> c !=<\/span> EOF)<\/span> {<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u7136\u540e\uff1a<\/p>\n\n\n\n
<\/a>fgets(<\/span>name,<\/span> sizeof<\/span>(<\/span>name),<\/span> stdin);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5b8c\u6574\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> age;<\/span><\/span>\n<\/a>char<\/span> name[<\/span>50<\/span>];<\/span><\/span>\n<\/a><\/span>\n<\/a>scanf(<\/span>\"<\/span>%d<\/span>\"<\/span>,<\/span> &<\/span>age);<\/span><\/span>\n<\/a><\/span>\n<\/a>int<\/span> c;<\/span><\/span>\n<\/a>while<\/span> ((<\/span>c =<\/span> getchar())<\/span> !=<\/span> '<\/span>\\n<\/span>'<\/span> &&<\/span> c !=<\/span> EOF)<\/span> {<\/span><\/span>\n<\/a>}<\/span><\/span>\n<\/a><\/span>\n<\/a>fgets(<\/span>name,<\/span> sizeof<\/span>(<\/span>name),<\/span> stdin);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
\u5341\u4e03\u3001\u6307\u9488\u9519\u8bef<\/h1>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> a =<\/span> 10<\/span>;<\/span><\/span>\n<\/a><\/span>\n<\/a>int<\/span> *<\/span>p;<\/span><\/span>\n<\/a><\/span>\n<\/a>*<\/span>p =<\/span> 20<\/span>;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8fd9\u91cc\uff1a<\/p>\n\n\n\n
p<\/code><\/pre>\n\n\n\n
\u6ca1\u6709\u521d\u59cb\u5316\u3002<\/p>\n\n\n\n
\u5b83\u91cc\u9762\u53ef\u80fd\u662f\u4e00\u4e2a\u968f\u673a\u5730\u5740\u3002<\/p>\n\n\n\n
\u8fd9\u5c31\u662f\u5371\u9669\u7684\u3002<\/p>\n\n\n\n
\u6b63\u786e\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> a =<\/span> 10<\/span>;<\/span><\/span>\n<\/a><\/span>\n<\/a>int<\/span> *<\/span>p =<\/span> &<\/span>a;<\/span><\/span>\n<\/a><\/span>\n<\/a>*<\/span>p =<\/span> 20<\/span>;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
\u5341\u516b\u3001\u91ce\u6307\u9488<\/h1>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p;<\/span><\/span>\n<\/a><\/span>\n<\/a>printf(<\/span>\"<\/span>%d\\n<\/span>\"<\/span>,<\/span> *<\/span>p);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
p<\/code> \u6ca1\u6709\u6307\u5411\u6709\u6548\u5185\u5b58\u3002<\/p>\n\n\n\n
\u4e0d\u8981\u8fd9\u6837\u5199\u3002<\/p>\n\n\n\n
\u63a8\u8350\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> NULL;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5982\u679c\u6682\u65f6\u6ca1\u6709\u6307\u5411\u5bf9\u8c61\uff1a<\/p>\n\n\n\n
\u660e\u786e\u8bbe\u4e3a NULL<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u5341\u4e5d\u3001\u60ac\u7a7a\u6307\u9488<\/h1>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span>\n<\/a><\/span>\n<\/a>*<\/span>p =<\/span> 100<\/span>;<\/span><\/span>\n<\/a><\/span>\n<\/a>free(<\/span>p);<\/span><\/span>\n<\/a><\/span>\n<\/a>printf(<\/span>\"<\/span>%d\\n<\/span>\"<\/span>,<\/span> *<\/span>p);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u91ca\u653e\u4ee5\u540e\uff1a<\/p>\n\n\n\n
p\n\u2193\n\u65e7\u5730\u5740\n\u2193\n\u5185\u5b58\u5df2\u7ecf\u91ca\u653e<\/code><\/pre>\n\n\n\n
\u8fd9\u65f6\u5019\u4f7f\u7528 *p<\/code> \u5c31\u662f\uff1a<\/p>\n\n\n\n
use-after-free\u3002<\/strong><\/p>\n\n\n\n
\n\n\n\n
\u4e8c\u5341\u3001\u63a8\u8350 free \u540e\u7f6e NULL<\/h1>\n\n\n\n
<\/a>free(<\/span>p);<\/span><\/span>\n<\/a>p =<\/span> NULL;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8fd9\u6837\u53ef\u4ee5\u964d\u4f4e\u8bef\u7528\u65e7\u5730\u5740\u7684\u98ce\u9669\u3002<\/p>\n\n\n\n
\u4f46\u6ce8\u610f\uff1a<\/p>\n\n\n\n
free(p)<\/code><\/pre>\n\n\n\n
\u5df2\u7ecf\u5b8c\u6210\u91ca\u653e\u3002<\/p>\n\n\n\n
<\/a>p =<\/span> NULL;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u53ea\u662f\u8ba9\u6307\u9488\u4e0d\u518d\u4fdd\u5b58\u90a3\u4e2a\u65e7\u5730\u5740\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e8c\u5341\u4e00\u3001double free<\/h1>\n\n\n\n
\u9519\u8bef\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span>\n<\/a><\/span>\n<\/a>free(<\/span>p);<\/span><\/span>\n<\/a>free(<\/span>p);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u540c\u4e00\u5757\u5185\u5b58\u88ab\u91ca\u653e\u4e24\u6b21\u3002<\/p>\n\n\n\n
\u8fd9\u662f\u4e25\u91cd\u7684\u5185\u5b58\u7ba1\u7406\u9519\u8bef\u3002<\/p>\n\n\n\n
\u63a8\u8350\uff1a<\/p>\n\n\n\n
<\/a>free(<\/span>p);<\/span><\/span>\n<\/a>p =<\/span> NULL;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5e76\u4e14\u4ece\u8bbe\u8ba1\u4e0a\u660e\u786e\uff1a<\/p>\n\n\n\n
\u54ea\u4e00\u6bb5\u4ee3\u7801\u8d1f\u8d23\u91ca\u653e\u8fd9\u5757\u5185\u5b58\u3002<\/strong><\/p>\n\n\n\n
\n\n\n\n
\u4e8c\u5341\u4e8c\u3001\u5185\u5b58\u6cc4\u6f0f<\/h1>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>void<\/span> test()<\/span> {<\/span><\/span>\n<\/a><\/span>\n<\/a>    int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> 100<\/span>);<\/span><\/span>\n<\/a><\/span>\n<\/a>    \/\/ \u4f7f\u7528 p<\/span><\/span>\n<\/a><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5982\u679c\u6ca1\u6709\uff1a<\/p>\n\n\n\n
<\/a>free(<\/span>p);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u90a3\u4e48\u7533\u8bf7\u7684\u5185\u5b58\u53ef\u80fd\u65e0\u6cd5\u518d\u88ab\u7a0b\u5e8f\u8bbf\u95ee\u3002<\/p>\n\n\n\n
\u5c31\u662f\uff1a<\/p>\n\n\n\n
\u5185\u5b58\u6cc4\u6f0f\u3002<\/strong><\/p>\n\n\n\n
\n\n\n\n
\u4e8c\u5341\u4e09\u3001malloc \u548c free\n\u5fc5\u987b\u914d\u5bf9<\/h1>\n\n\n\n
\u53ef\u4ee5\u517b\u6210\uff1a<\/p>\n\n\n\n
malloc\n \u2193\n\u4f7f\u7528\n \u2193\nfree<\/code><\/pre>\n\n\n\n
\u7684\u4e60\u60ef\u3002<\/p>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> 10<\/span>);<\/span><\/span>\n<\/a><\/span>\n<\/a>if<\/span> (<\/span>p ==<\/span> NULL)<\/span> {<\/span><\/span>\n<\/a>    return<\/span> 1<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span>\n<\/a><\/span>\n<\/a>\/* \u4f7f\u7528 *\/<\/span><\/span>\n<\/a><\/span>\n<\/a>free(<\/span>p);<\/span><\/span>\n<\/a>p =<\/span> NULL;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
\u4e8c\u5341\u56db\u3001realloc \u7684\u5751<\/h1>\n\n\n\n
\u5371\u9669\u5199\u6cd5\uff1a<\/p>\n\n\n\n
<\/a>p =<\/span> realloc(<\/span>p,<\/span> new_size);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5982\u679c\u5931\u8d25\uff1a<\/p>\n\n\n\n
realloc \u8fd4\u56de NULL<\/code><\/pre>\n\n\n\n
\u90a3\u4e48\u539f\u6765\u7684\u6307\u9488\u53ef\u80fd\u5df2\u7ecf\u65e0\u6cd5\u901a\u8fc7 p<\/code> \u4fdd\u5b58\u3002<\/p>\n\n\n\n
\u66f4\u63a8\u8350\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>temp =<\/span> realloc(<\/span>p,<\/span> new_size);<\/span><\/span>\n<\/a><\/span>\n<\/a>if<\/span> (<\/span>temp ==<\/span> NULL)<\/span> {<\/span><\/span>\n<\/a>    \/\/ p \u4ecd\u7136\u6709\u6548<\/span><\/span>\n<\/a>}<\/span> else<\/span> {<\/span><\/span>\n<\/a>    p =<\/span> temp;<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
\u4e8c\u5341\u4e94\u3001\u7ed3\u6784\u4f53\u6307\u9488\u9519\u8bef<\/h1>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>typedef<\/span> struct<\/span> {<\/span><\/span>\n<\/a>    int<\/span> age;<\/span><\/span>\n<\/a>}<\/span> Student;<\/span><\/span>\n<\/a><\/span>\n<\/a>Student *<\/span>p =<\/span> NULL;<\/span><\/span>\n<\/a><\/span>\n<\/a>p-><\/span>age =<\/span> 18<\/span>;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u9519\u8bef\u3002<\/p>\n\n\n\n
\u56e0\u4e3a\uff1a<\/p>\n\n\n\n
p\n\u2193\nNULL<\/code><\/pre>\n\n\n\n
\u4e0d\u80fd\u4f7f\u7528\uff1a<\/p>\n\n\n\n
<\/a>p-><\/span>age<\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
\u4e8c\u5341\u516d\u3001.<\/code> \u548c -><\/code>\n\u5199\u9519<\/h1>\n\n\n\n
\u7ed3\u6784\u4f53\u53d8\u91cf\uff1a<\/p>\n\n\n\n
<\/a>Student s;<\/span><\/span>\n<\/a><\/span>\n<\/a>s.<\/span>age =<\/span> 18<\/span>;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u7ed3\u6784\u4f53\u6307\u9488\uff1a<\/p>\n\n\n\n
<\/a>Student *<\/span>p =<\/span> &<\/span>s;<\/span><\/span>\n<\/a><\/span>\n<\/a>p-><\/span>age =<\/span> 18<\/span>;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4e0d\u8981\u5199\u53cd\uff1a<\/p>\n\n\n\n
<\/a>p.<\/span>age<\/span><\/code><\/pre><\/div>\n\n\n\n
\u4e5f\u4e0d\u8981\u5728\u666e\u901a\u7ed3\u6784\u4f53\u53d8\u91cf\u4e0a\u968f\u610f\uff1a<\/p>\n\n\n\n
<\/a>s-><\/span>age<\/span><\/code><\/pre><\/div>\n\n\n\n
\u7b80\u5355\u8bb0\uff1a<\/p>\n\n\n\n
\u53d8\u91cf\n\u2193\n.\n\n\u6307\u9488\n\u2193\n-><\/code><\/pre>\n\n\n\n
\n\n\n\n
\u4e8c\u5341\u4e03\u3001\u6587\u4ef6\u64cd\u4f5c\u7684\u5751<\/h1>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>FILE<\/span> *<\/span>fp =<\/span> fopen(<\/span>\"data.txt\"<\/span>,<\/span> \"r\"<\/span>);<\/span><\/span>\n<\/a><\/span>\n<\/a>fscanf(<\/span>fp,<\/span> \"<\/span>%d<\/span>\"<\/span>,<\/span> &<\/span>x);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5982\u679c\uff1a<\/p>\n\n\n\n
data.txt\n\u4e0d\u5b58\u5728<\/code><\/pre>\n\n\n\n
\u90a3\u4e48\uff1a<\/p>\n\n\n\n
fp == NULL<\/code><\/pre>\n\n\n\n
\u7ee7\u7eed\u4f7f\u7528\uff1a<\/p>\n\n\n\n
<\/a>fscanf(<\/span>fp,<\/span> ...);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5c31\u53ef\u80fd\u51fa\u95ee\u9898\u3002<\/p>\n\n\n\n
\u6240\u4ee5\uff1a<\/p>\n\n\n\n
<\/a>if<\/span> (<\/span>fp ==<\/span> NULL)<\/span> {<\/span><\/span>\n<\/a>    printf(<\/span>\"\u6253\u5f00\u5931\u8d25<\/span>\\n<\/span>\"<\/span>);<\/span><\/span>\n<\/a>    return<\/span> 1<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
\u4e8c\u5341\u516b\u3001\u4e0d\u8981\u5fd8\u8bb0 fclose<\/h1>\n\n\n\n
\u6253\u5f00\uff1a<\/p>\n\n\n\n
<\/a>FILE<\/span> *<\/span>fp =<\/span> fopen(...);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u7ed3\u675f\uff1a<\/p>\n\n\n\n
<\/a>fclose(<\/span>fp);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u6587\u4ef6\u64cd\u4f5c\u57fa\u672c\u4e60\u60ef\uff1a<\/p>\n\n\n\n
fopen\n\u2193\n\u68c0\u67e5 NULL\n\u2193\n\u8bfb\/\u5199\n\u2193\nfclose<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u4e8c\u5341\u4e5d\u3001\u6587\u4ef6\u6a21\u5f0f\u5199\u9519<\/h1>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>fopen(<\/span>\"data.txt\"<\/span>,<\/span> \"w\"<\/span>);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4f1a\u8986\u76d6\u539f\u6587\u4ef6\u3002<\/p>\n\n\n\n
\u5982\u679c\u53ea\u662f\u60f3\u8ffd\u52a0\uff1a<\/p>\n\n\n\n
<\/a>fopen(<\/span>\"data.txt\"<\/span>,<\/span> \"a\"<\/span>);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5982\u679c\u53ea\u60f3\u8bfb\u53d6\uff1a<\/p>\n\n\n\n
<\/a>fopen(<\/span>\"data.txt\"<\/span>,<\/span> \"r\"<\/span>);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u6240\u4ee5\u4f7f\u7528 fopen()<\/code> \u65f6\uff0c\u8981\u5148\u60f3\u6e05\u695a\uff1a<\/p>\n\n\n\n
\u6211\u8981\u8bfb\u53d6\uff1f\n\u6211\u8981\u8986\u76d6\u5199\uff1f\n\u6211\u8981\u8ffd\u52a0\uff1f\n\u6211\u8981\u4e8c\u8fdb\u5236\uff1f<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u4e09\u5341\u3001\u903b\u8f91\u9519\u8bef<\/h1>\n\n\n\n
\u8fd9\u662f\u6700\u9ebb\u70e6\u7684\u4e00\u7c7b\uff1a<\/p>\n\n\n\n
\u7a0b\u5e8f\u4e0d\u5d29\u6e83\uff0c\u4f46\u662f\u7ed3\u679c\u4e0d\u5bf9\u3002<\/strong><\/p>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> sum =<\/span> 0<\/span>;<\/span><\/span>\n<\/a><\/span>\n<\/a>for<\/span> (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i <<\/span> 10<\/span>;<\/span> i++)<\/span> {<\/span><\/span>\n<\/a>    sum +=<\/span> i;<\/span><\/span>\n<\/a>}<\/span><\/span>\n<\/a><\/span>\n<\/a>printf(<\/span>\"<\/span>%d\\n<\/span>\"<\/span>,<\/span> sum);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5982\u679c\u4f60\u672c\u6765\u60f3\u8ba1\u7b97\uff1a<\/p>\n\n\n\n
1 + 2 + ... + 10<\/code><\/pre>\n\n\n\n
\u90a3\u4e48\u7ed3\u679c\u663e\u7136\u4e0d\u5bf9\u3002<\/p>\n\n\n\n
\u4f46\u662f\uff1a<\/p>\n\n\n\n
\u7f16\u8bd1\u6210\u529f\n\u7a0b\u5e8f\u8fd0\u884c\n\u751a\u81f3\u5b8c\u5168\u4e0d\u5d29\u6e83<\/code><\/pre>\n\n\n\n
\u8fd9\u5c31\u662f\uff1a<\/p>\n\n\n\n
\u903b\u8f91\u9519\u8bef\u3002<\/strong><\/p>\n\n\n\n
\n\n\n\n
\u4e09\u5341\u4e00\u3001\u8c03\u8bd5\u7684\u6838\u5fc3\u601d\u60f3<\/h1>\n\n\n\n
\u4e0d\u8981\u770b\u5230 Bug \u5c31\u76f4\u63a5\u4e71\u6539\u3002<\/p>\n\n\n\n
\u63a8\u8350\uff1a<\/p>\n\n\n\n
\u53d1\u73b0\u95ee\u9898\n \u2193\n\u590d\u73b0\u95ee\u9898\n \u2193\n\u786e\u5b9a\u9519\u8bef\u53d1\u751f\u7684\u4f4d\u7f6e\n \u2193\n\u89c2\u5bdf\u53d8\u91cf\n \u2193\n\u7f29\u5c0f\u8303\u56f4\n \u2193\n\u627e\u5230\u539f\u56e0\n \u2193\n\u4fee\u6539\n \u2193\n\u91cd\u65b0\u6d4b\u8bd5<\/code><\/pre>\n\n\n\n
\u8fd9\u624d\u662f\u8c03\u8bd5\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e09\u5341\u4e8c\u3001\u7b2c\u4e00\u79cd\u65b9\u6cd5\uff1aprintf\n\u8c03\u8bd5<\/h1>\n\n\n\n
\u6700\u7b80\u5355\u7684\u8c03\u8bd5\u65b9\u6cd5\uff1a<\/p>\n\n\n\n
<\/a>printf()<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> a =<\/span> 10<\/span>;<\/span><\/span>\n<\/a>int<\/span> b =<\/span> 20<\/span>;<\/span><\/span>\n<\/a><\/span>\n<\/a>printf(<\/span>\"DEBUG: a = <\/span>%d\\n<\/span>\"<\/span>,<\/span> a);<\/span><\/span>\n<\/a>printf(<\/span>\"DEBUG: b = <\/span>%d\\n<\/span>\"<\/span>,<\/span> b);<\/span><\/span>\n<\/a><\/span>\n<\/a>int<\/span> c =<\/span> a +<\/span> b;<\/span><\/span>\n<\/a><\/span>\n<\/a>printf(<\/span>\"DEBUG: c = <\/span>%d\\n<\/span>\"<\/span>,<\/span> c);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u901a\u8fc7\u8f93\u51fa\uff1a<\/p>\n\n\n\n
DEBUG: a = 10\nDEBUG: b = 20\nDEBUG: c = 30<\/code><\/pre>\n\n\n\n
\u9010\u6b65\u89c2\u5bdf\u7a0b\u5e8f\u72b6\u6001\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e09\u5341\u4e09\u3001\u4e3a\u4ec0\u4e48 printf \u5f88\u6709\u7528<\/h1>\n\n\n\n
\u5047\u8bbe\uff1a<\/p>\n\n\n\n
<\/a>for<\/span> (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i <<\/span> n;<\/span> i++)<\/span> {<\/span><\/span>\n<\/a>    arr[<\/span>i]<\/span> *=<\/span> 2<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u7ed3\u679c\u4e0d\u5bf9\u3002<\/p>\n\n\n\n
\u53ef\u4ee5\uff1a<\/p>\n\n\n\n
<\/a>for<\/span> (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i <<\/span> n;<\/span> i++)<\/span> {<\/span><\/span>\n<\/a><\/span>\n<\/a>    printf(<\/span><\/span>\n<\/a>        \"DEBUG: i=<\/span>%d<\/span> arr[i]=<\/span>%d\\n<\/span>\"<\/span>,<\/span><\/span>\n<\/a>        i,<\/span><\/span>\n<\/a>        arr[<\/span>i]<\/span><\/span>\n<\/a>    );<\/span><\/span>\n<\/a><\/span>\n<\/a>    arr[<\/span>i]<\/span> *=<\/span> 2<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8fd9\u6837\u5c31\u53ef\u4ee5\u770b\u5230\uff1a<\/p>\n\n\n\n
\u5230\u5e95\u662f\u54ea\u4e00\u6b21\u5faa\u73af\u51fa\u4e86\u95ee\u9898<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u4e09\u5341\u56db\u3001\u6253\u5370\u5730\u5740<\/h1>\n\n\n\n
\u5b66\u8fc7\u6307\u9488\u4e4b\u540e\uff0c\u53ef\u4ee5\u6253\u5370\u5730\u5740\uff1a<\/p>\n\n\n\n
<\/a>printf(<\/span>\"<\/span>%p\\n<\/span>\"<\/span>,<\/span> (<\/span>void<\/span> *)<\/span>p);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> a =<\/span> 10<\/span>;<\/span><\/span>\n<\/a>int<\/span> *<\/span>p =<\/span> &<\/span>a;<\/span><\/span>\n<\/a><\/span>\n<\/a>printf(<\/span>\"a address = <\/span>%p\\n<\/span>\"<\/span>,<\/span> (<\/span>void<\/span> *)&<\/span>a);<\/span><\/span>\n<\/a>printf(<\/span>\"p value   = <\/span>%p\\n<\/span>\"<\/span>,<\/span> (<\/span>void<\/span> *)<\/span>p);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5e94\u8be5\u770b\u5230\uff1a<\/p>\n\n\n\n
a address = ...\np value   = ...<\/code><\/pre>\n\n\n\n
\u4e24\u8005\u5e94\u8be5\u5bf9\u5e94\u540c\u4e00\u4e2a\u5730\u5740\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e09\u5341\u4e94\u3001\u6253\u5370\u7ed3\u6784\u4f53\u72b6\u6001<\/h1>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>printf(<\/span><\/span>\n<\/a>    \"name=<\/span>%s<\/span> age=<\/span>%d<\/span> score=<\/span>%.2f\\n<\/span>\"<\/span>,<\/span><\/span>\n<\/a>    s.<\/span>name,<\/span><\/span>\n<\/a>    s.<\/span>age,<\/span><\/span>\n<\/a>    s.<\/span>score<\/span>\n<\/a>);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u7279\u522b\u9002\u5408\uff1a<\/p>\n\n\n\n
\u5b66\u751f\u7ba1\u7406\u7cfb\u7edf\n\u8bfe\u7a0b\u8868\n\u914d\u7f6e\u6587\u4ef6<\/code><\/pre>\n\n\n\n
\u8fd9\u7c7b\u9879\u76ee\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e09\u5341\u516d\u3001\u7b2c\u4e8c\u79cd\u65b9\u6cd5\uff1aGDB<\/h1>\n\n\n\n
printf<\/code> \u662f\u6700\u7b80\u5355\u7684\u8c03\u8bd5\u65b9\u5f0f\u3002<\/p>\n\n\n\n
\u66f4\u4e13\u4e1a\u7684\u662f\uff1a<\/p>\n\n\n\n
GDB<\/strong><\/p>\n\n\n\n
GDB \u662f\uff1a<\/p>\n\n\n\n
GNU Debugger<\/strong><\/p>\n\n\n\n
\u53ef\u4ee5\uff1a<\/p>\n\n\n\n
\u8bbe\u7f6e\u65ad\u70b9\n\u5355\u6b65\u6267\u884c\n\u67e5\u770b\u53d8\u91cf\n\u67e5\u770b\u8c03\u7528\u6808\n\u67e5\u770b\u5185\u5b58<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u4e09\u5341\u4e03\u3001\u4f7f\u7528 -g \u7f16\u8bd1<\/h1>\n\n\n\n
\u4f7f\u7528 GDB \u65f6\uff1a<\/p>\n\n\n\n
<\/a>gcc<\/span> -g<\/span> main.c -o<\/span> main<\/span><\/code><\/pre><\/div>\n\n\n\n
-g<\/code> \u4f1a\u52a0\u5165\u8c03\u8bd5\u4fe1\u606f\u3002<\/p>\n\n\n\n
\u591a\u6587\u4ef6\uff1a<\/p>\n\n\n\n
<\/a>gcc<\/span> -g<\/span> main.c student.c file.c -o<\/span> main<\/span><\/code><\/pre><\/div>\n\n\n\n
\u7136\u540e\uff1a<\/p>\n\n\n\n
<\/a>gdb<\/span> .\/main<\/span><\/code><\/pre><\/div>\n\n\n\n
Windows \u4e0b\u5982\u679c\u4f7f\u7528 MinGW\/GDB\uff0c\u5219\u547d\u4ee4\u5f62\u5f0f\u901a\u5e38\u7c7b\u4f3c\uff1a<\/p>\n\n\n\n
<\/a>gdb<\/span> main.exe<\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
\u4e09\u5341\u516b\u3001GDB \u8bbe\u7f6e\u65ad\u70b9<\/h1>\n\n\n\n
\u8fdb\u5165 GDB\uff1a<\/p>\n\n\n\n
<\/a>gdb<\/span> .\/main<\/span><\/code><\/pre><\/div>\n\n\n\n
\u8bbe\u7f6e\uff1a<\/p>\n\n\n\n
break main<\/code><\/pre>\n\n\n\n
\u6216\u8005\uff1a<\/p>\n\n\n\n
break 10<\/code><\/pre>\n\n\n\n
\u7136\u540e\u8fd0\u884c\uff1a<\/p>\n\n\n\n
run<\/code><\/pre>\n\n\n\n
\u7a0b\u5e8f\u4f1a\u5728\u65ad\u70b9\u6682\u505c\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e09\u5341\u4e5d\u3001\u5355\u6b65\u6267\u884c<\/h1>\n\n\n\n
\u5e38\u89c1\u547d\u4ee4\uff1a<\/p>\n\n\n\n
next<\/code><\/pre>\n\n\n\n
\u6267\u884c\u4e0b\u4e00\u884c\u3002<\/p>\n\n\n\n
step<\/code><\/pre>\n\n\n\n
\u8fdb\u5165\u51fd\u6570\u3002<\/p>\n\n\n\n
continue<\/code><\/pre>\n\n\n\n
\u7ee7\u7eed\u8fd0\u884c\u5230\u4e0b\u4e00\u4e2a\u65ad\u70b9\u3002<\/p>\n\n\n\n
\n\n\n\n
\u56db\u5341\u3001\u67e5\u770b\u53d8\u91cf<\/h1>\n\n\n\n
GDB\uff1a<\/p>\n\n\n\n
print a<\/code><\/pre>\n\n\n\n
\u6216\u8005\uff1a<\/p>\n\n\n\n
p a<\/code><\/pre>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
(gdb) p a\n$1 = 10<\/code><\/pre>\n\n\n\n
\u67e5\u770b\u6307\u9488\uff1a<\/p>\n\n\n\n
p p<\/code><\/pre>\n\n\n\n
\u67e5\u770b\u6307\u9488\u6307\u5411\u7684\u503c\uff1a<\/p>\n\n\n\n
p *p<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u56db\u5341\u4e00\u3001\u67e5\u770b\u8c03\u7528\u6808<\/h1>\n\n\n\n
\u5982\u679c\u7a0b\u5e8f\u5d29\u6e83\uff0c\u53ef\u4ee5\u4f7f\u7528\uff1a<\/p>\n\n\n\n
backtrace<\/code><\/pre>\n\n\n\n
\u6216\u8005\uff1a<\/p>\n\n\n\n
bt<\/code><\/pre>\n\n\n\n
\u5b83\u53ef\u4ee5\u663e\u793a\uff1a<\/p>\n\n\n\n
main()\n \u2193\nfoo()\n \u2193\nbar()\n \u2193\n\u5d29\u6e83<\/code><\/pre>\n\n\n\n
\u8fd9\u6837\u53ef\u4ee5\u77e5\u9053\uff1a<\/p>\n\n\n\n
\u7a0b\u5e8f\u662f\u4ece\u4ec0\u4e48\u51fd\u6570\u4e00\u8def\u8d70\u5230\u9519\u8bef\u4f4d\u7f6e\u7684\u3002<\/strong><\/p>\n\n\n\n
\n\n\n\n
\u56db\u5341\u4e8c\u3001\u7b2c\u4e09\u79cd\u65b9\u6cd5\uff1aSanitizer<\/h1>\n\n\n\n
\u73b0\u4ee3 GCC \/ Clang \u4e2d\u975e\u5e38\u6709\u7528\u7684\u5de5\u5177\uff1a<\/p>\n\n\n\n
AddressSanitizer<\/strong><\/p>\n\n\n\n
\u7b80\u79f0\uff1a<\/p>\n\n\n\n
ASan<\/code><\/pre>\n\n\n\n
\u53ef\u4ee5\u5e2e\u52a9\u53d1\u73b0\uff1a<\/p>\n\n\n\n
\u6570\u7ec4\u8d8a\u754c\nuse-after-free\ndouble free\n\u90e8\u5206\u5185\u5b58\u95ee\u9898<\/code><\/pre>\n\n\n\n
\u7f16\u8bd1\uff1a<\/p>\n\n\n\n
<\/a>gcc<\/span> -fsanitize<\/span>=<\/span>address -g<\/span> main.c -o<\/span> main<\/span><\/code><\/pre><\/div>\n\n\n\n
\u591a\u6587\u4ef6\uff1a<\/p>\n\n\n\n
<\/a>gcc<\/span> -fsanitize<\/span>=<\/span>address -g<\/span> \\<\/span><\/span>\n<\/a>    main.c student.c file.c \\<\/span><\/span>\n<\/a>    -o<\/span> main<\/span><\/code><\/pre><\/div>\n\n\n\n
\u8fd0\u884c\u7a0b\u5e8f\u65f6\uff0c\u5982\u679c\u53d1\u751f\u5f88\u591a\u5178\u578b\u5185\u5b58\u9519\u8bef\uff0cSanitizer \u4f1a\u8f93\u51fa\u8be6\u7ec6\u62a5\u544a\u3002<\/p>\n\n\n\n
\n\n\n\n
\u56db\u5341\u4e09\u3001UndefinedBehaviorSanitizer<\/h1>\n\n\n\n
\u8fd8\u6709\uff1a<\/p>\n\n\n\n
UBSan<\/code><\/pre>\n\n\n\n
\u53ef\u4ee5\u68c0\u6d4b\u4e00\u4e9b\uff1a<\/p>\n\n\n\n
\u672a\u5b9a\u4e49\u884c\u4e3a<\/code><\/pre>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>gcc<\/span> -fsanitize<\/span>=<\/span>undefined -g<\/span> main.c -o<\/span> main<\/span><\/code><\/pre><\/div>\n\n\n\n
\u4e5f\u53ef\u4ee5\uff1a<\/p>\n\n\n\n
<\/a>gcc<\/span> -fsanitize<\/span>=<\/span>address,undefined -g<\/span> main.c -o<\/span> main<\/span><\/code><\/pre><\/div>\n\n\n\n
\u5f00\u53d1\u9636\u6bb5\u975e\u5e38\u6709\u5e2e\u52a9\u3002<\/p>\n\n\n\n
\n\n\n\n
\u56db\u5341\u56db\u3001Valgrind<\/h1>\n\n\n\n
Linux \u73af\u5883\u4e0b\u8fd8\u7ecf\u5e38\u4f7f\u7528\uff1a<\/p>\n\n\n\n
Valgrind<\/code><\/pre>\n\n\n\n
\u5b83\u53ef\u4ee5\u5e2e\u52a9\u68c0\u67e5\uff1a<\/p>\n\n\n\n
\u5185\u5b58\u6cc4\u6f0f\n\u975e\u6cd5\u5185\u5b58\u8bbf\u95ee\n\u672a\u521d\u59cb\u5316\u5185\u5b58<\/code><\/pre>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>valgrind<\/span> --leak-check<\/span>=<\/span>full .\/main<\/span><\/code><\/pre><\/div>\n\n\n\n
\u4e0d\u8fc7\u4e0d\u540c\u7cfb\u7edf\u4e0a\u7684\u53ef\u7528\u6027\u548c\u5b89\u88c5\u65b9\u5f0f\u4e0d\u540c\u3002<\/p>\n\n\n\n
\u5f53\u524d\u9636\u6bb5\u77e5\u9053\uff1a<\/p>\n\n\n\n
GDB\nSanitizer\nValgrind<\/code><\/pre>\n\n\n\n
\u5206\u522b\u7528\u4e8e\u4e0d\u540c\u7c7b\u578b\u7684\u8c03\u8bd5\u5373\u53ef\u3002<\/p>\n\n\n\n
\n\n\n\n
\u56db\u5341\u4e94\u3001Makefile \u52a0\u5165\u8c03\u8bd5\u9009\u9879<\/h1>\n\n\n\n
\u4e4b\u524d\u5b66\u4e60\u4e86\uff1a<\/p>\n\n\n\n
CC = gcc\nCFLAGS = -Wall -Wextra<\/code><\/pre>\n\n\n\n
\u8c03\u8bd5\u65f6\u53ef\u4ee5\uff1a<\/p>\n\n\n\n
CC = gcc\nCFLAGS = -Wall -Wextra -g -fsanitize=address,undefined<\/code><\/pre>\n\n\n\n
\u7136\u540e\uff1a<\/p>\n\n\n\n
<\/a>make<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8fd9\u6837\u6574\u4e2a\u9879\u76ee\u90fd\u4f1a\u4f7f\u7528\u8c03\u8bd5\u9009\u9879\u6784\u5efa\u3002<\/p>\n\n\n\n
\n\n\n\n
\u56db\u5341\u516d\u3001Debug \u548c Release<\/h1>\n\n\n\n
\u9879\u76ee\u8f83\u5927\u4ee5\u540e\uff0c\u7ecf\u5e38\u533a\u5206\uff1a<\/p>\n\n\n\n
Debug\nRelease<\/code><\/pre>\n\n\n\n
Debug\uff1a<\/p>\n\n\n\n
\u65b9\u4fbf\u8c03\u8bd5\n\u4fdd\u7559\u8c03\u8bd5\u4fe1\u606f\n\u542f\u7528\u68c0\u67e5<\/code><\/pre>\n\n\n\n
Release\uff1a<\/p>\n\n\n\n
\u7528\u4e8e\u6b63\u5f0f\u53d1\u5e03\n\u901a\u5e38\u4f7f\u7528\u4f18\u5316\n\u53ef\u80fd\u5173\u95ed\u90e8\u5206\u8c03\u8bd5\u9009\u9879<\/code><\/pre>\n\n\n\n
\u7b80\u5355 Makefile \u53ef\u4ee5\uff1a<\/p>\n\n\n\n
CFLAGS_DEBUG = -Wall -Wextra -g -fsanitize=address,undefined\nCFLAGS_RELEASE = -Wall -Wextra -O2<\/code><\/pre>\n\n\n\n
\u4ee5\u540e\u518d\u6839\u636e\u9700\u8981\u9009\u62e9\u3002<\/p>\n\n\n\n
\n\n\n\n
\u56db\u5341\u4e03\u3001\u7f16\u8bd1\u4f18\u5316<\/h1>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>gcc<\/span> -O2<\/span> main.c -o<\/span> main<\/span><\/code><\/pre><\/div>\n\n\n\n
-O2<\/code> \u8868\u793a\u5f00\u542f\u4e00\u5b9a\u7a0b\u5ea6\u7684\u4f18\u5316\u3002<\/p>\n\n\n\n
\u4f46\u662f\u8c03\u8bd5\u9636\u6bb5\u901a\u5e38\u4e0d\u5efa\u8bae\u4e00\u5f00\u59cb\u5c31\u8ffd\u6c42\u9ad8\u4f18\u5316\u3002<\/p>\n\n\n\n
\u6bd4\u8f83\u9002\u5408\uff1a<\/p>\n\n\n\n
\u5f00\u53d1 \/ \u8c03\u8bd5\n\u2193\n-g\n\u2193\nSanitizer\n\n\u53d1\u5e03\n\u2193\n-O2<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u56db\u5341\u516b\u3001\u9047\u5230 Bug\n\u65f6\u5148\u770b\u9519\u8bef\u4fe1\u606f<\/h1>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
main.c:25:10:\nerror: ...<\/code><\/pre>\n\n\n\n
\u8fd9\u91cc\u5305\u542b\uff1a<\/p>\n\n\n\n
\u6587\u4ef6\n\u884c\u53f7\n\u5217\u53f7\n\u9519\u8bef\u4fe1\u606f<\/code><\/pre>\n\n\n\n
\u6240\u4ee5\u9996\u5148\u770b\uff1a<\/p>\n\n\n\n
\u54ea\u4e2a\u6587\u4ef6\uff1f\n\u54ea\u4e00\u884c\uff1f\n\u4ec0\u4e48\u9519\u8bef\uff1f<\/code><\/pre>\n\n\n\n
\u800c\u4e0d\u662f\u76f4\u63a5\u4ece\u5934\u5230\u5c3e\u4e71\u627e\u3002<\/p>\n\n\n\n
\n\n\n\n
\u56db\u5341\u4e5d\u3001\u9519\u8bef\u884c\u4e0d\u4e00\u5b9a\u662f\u771f\u6b63\u539f\u56e0<\/h1>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> NULL;<\/span><\/span>\n<\/a><\/span>\n<\/a>foo(<\/span>p);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u7136\u540e\uff1a<\/p>\n\n\n\n
<\/a>void<\/span> foo(<\/span>int<\/span> *<\/span>p)<\/span> {<\/span><\/span>\n<\/a>    printf(<\/span>\"<\/span>%d\\n<\/span>\"<\/span>,<\/span> *<\/span>p);<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u7a0b\u5e8f\u53ef\u80fd\u5728\uff1a<\/p>\n\n\n\n
printf<\/code><\/pre>\n\n\n\n
\u8fd9\u91cc\u5d29\u6e83\u3002<\/p>\n\n\n\n
\u4f46\u662f\uff1a<\/p>\n\n\n\n
\u771f\u6b63\u7684\u95ee\u9898\u53ef\u80fd\u65e9\u5728 main()<\/code> \u91cc\u4f20\u5165\u4e86\nNULL\u3002<\/strong><\/p>\n\n\n\n
\u6240\u4ee5\u8c03\u8bd5\u4e0d\u80fd\u53ea\u76ef\u7740\u5d29\u6e83\u7684\u90a3\u4e00\u884c\u3002<\/p>\n\n\n\n
\u8981\u6cbf\u7740\uff1a<\/p>\n\n\n\n
\u6570\u636e\u6765\u6e90\n\u2193\n\u51fd\u6570\u8c03\u7528\n\u2193\n\u53d8\u91cf\u53d8\u5316\n\u2193\n\u6700\u7ec8\u9519\u8bef<\/code><\/pre>\n\n\n\n
\u5f80\u56de\u8ffd\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e94\u5341\u3001\u6700\u5b9e\u7528\u7684\u8c03\u8bd5\u601d\u8def\uff1a\u7f29\u5c0f\u8303\u56f4<\/h1>\n\n\n\n
\u5047\u8bbe\uff1a<\/p>\n\n\n\n
\u7a0b\u5e8f\u8f93\u51fa\u9519\u8bef<\/code><\/pre>\n\n\n\n
\u4e0d\u8981\u4e00\u6b21\u6539 20 \u884c\u3002<\/p>\n\n\n\n
\u53ef\u4ee5\uff1a<\/p>\n\n\n\n
\u5148\u786e\u8ba4\u8f93\u5165\u662f\u5426\u6b63\u786e\n\u2193\n\u786e\u8ba4\u53d8\u91cf\n\u2193\n\u786e\u8ba4\u5faa\u73af\u6b21\u6570\n\u2193\n\u786e\u8ba4\u4e2d\u95f4\u7ed3\u679c\n\u2193\n\u786e\u8ba4\u6700\u7ec8\u7ed3\u679c<\/code><\/pre>\n\n\n\n
\u4e00\u6b21\u53ea\u6392\u9664\u4e00\u4e2a\u53ef\u80fd\u6027\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e94\u5341\u4e00\u3001\u4e8c\u5206\u6cd5\u8c03\u8bd5<\/h1>\n\n\n\n
\u7a0b\u5e8f\u6709 1000 \u884c\u3002<\/p>\n\n\n\n
\u4e0d\u77e5\u9053\u54ea\u91cc\u9519\u3002<\/p>\n\n\n\n
\u53ef\u4ee5\u5148\uff1a<\/p>\n\n\n\n
\u68c0\u67e5\u524d 500 \u884c\u4ea7\u751f\u7684\u6570\u636e<\/code><\/pre>\n\n\n\n
\u5982\u679c\u6b63\u786e\uff1a<\/p>\n\n\n\n
\u9519\u8bef\u5728\u540e 500 \u884c<\/code><\/pre>\n\n\n\n
\u518d\uff1a<\/p>\n\n\n\n
\u68c0\u67e5 250 \u884c<\/code><\/pre>\n\n\n\n
\u4e0d\u65ad\u7f29\u5c0f\u8303\u56f4\u3002<\/p>\n\n\n\n
\u8fd9\u5c31\u662f\uff1a<\/p>\n\n\n\n
\u4e8c\u5206\u5b9a\u4f4d\u95ee\u9898\u3002<\/strong><\/p>\n\n\n\n
\n\n\n\n
\u4e94\u5341\u4e8c\u3001\u65ad\u8a00 assert<\/h1>\n\n\n\n
C \u6807\u51c6\u5e93\u63d0\u4f9b\uff1a<\/p>\n\n\n\n
<\/a>assert()<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u9700\u8981\uff1a<\/p>\n\n\n\n
<\/a>#include <\/span><assert.h><\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> age =<\/span> 18<\/span>;<\/span><\/span>\n<\/a><\/span>\n<\/a>assert(<\/span>age >=<\/span> 0<\/span>);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u5982\u679c\u6761\u4ef6\uff1a<\/p>\n\n\n\n
true<\/code><\/pre>\n\n\n\n
\u7ee7\u7eed\u6267\u884c\u3002<\/p>\n\n\n\n
\u5982\u679c\uff1a<\/p>\n\n\n\n
false<\/code><\/pre>\n\n\n\n
\u7a0b\u5e8f\u4f1a\u62a5\u544a\u65ad\u8a00\u5931\u8d25\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e94\u5341\u4e09\u3001assert \u7684\u7528\u9014<\/h1>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>void<\/span> process(<\/span>int<\/span> *<\/span>p)<\/span> {<\/span><\/span>\n<\/a><\/span>\n<\/a>    assert(<\/span>p !=<\/span> NULL);<\/span><\/span>\n<\/a><\/span>\n<\/a>    *<\/span>p =<\/span> 100<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u610f\u601d\u662f\uff1a<\/p>\n\n\n\n
\u6211\u8ba4\u4e3a\u8fdb\u5165\u8fd9\u4e2a\u51fd\u6570\u65f6\np \u5fc5\u987b\u4e0d\u662f NULL<\/code><\/pre>\n\n\n\n
\u5982\u679c\u7a0b\u5e8f\u51fa\u73b0\u8fdd\u53cd\u8fd9\u4e2a\u5047\u8bbe\u7684\u60c5\u51b5\uff1a<\/p>\n\n\n\n
\u7acb\u523b\u505c\u4e0b\u6765<\/code><\/pre>\n\n\n\n
\u8fd9\u5bf9\u5b9a\u4f4d Bug \u975e\u5e38\u65b9\u4fbf\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e94\u5341\u56db\u3001\u4e0d\u8981\u628a assert\n\u5f53\u666e\u901a\u8f93\u5165\u68c0\u67e5<\/h1>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> age;<\/span><\/span>\n<\/a>scanf(<\/span>\"<\/span>%d<\/span>\"<\/span>,<\/span> &<\/span>age);<\/span><\/span>\n<\/a><\/span>\n<\/a>assert(<\/span>age >=<\/span> 0<\/span>);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u7528\u6237\u8f93\u5165\uff1a<\/p>\n\n\n\n
-10<\/code><\/pre>\n\n\n\n
\u7a0b\u5e8f\u5c31\u9000\u51fa\u3002<\/p>\n\n\n\n
\u4f46\u5b9e\u9645\u7a0b\u5e8f\u53ef\u80fd\u5e94\u8be5\uff1a<\/p>\n\n\n\n
\u63d0\u793a\u9519\u8bef\n\u8981\u6c42\u91cd\u65b0\u8f93\u5165<\/code><\/pre>\n\n\n\n
\u6240\u4ee5\uff1a<\/p>\n\n\n\n
assert\n\u2193\n\u68c0\u67e5\u7a0b\u5e8f\u5458\u8ba4\u4e3a\u201c\u4e0d\u5e94\u8be5\u53d1\u751f\u201d\u7684\u60c5\u51b5<\/code><\/pre>\n\n\n\n
\u800c\u4e0d\u662f\u66ff\u4ee3\u6b63\u5e38\u7684\u7528\u6237\u8f93\u5165\u9a8c\u8bc1\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e94\u5341\u4e94\u3001\u5e38\u89c1\u5751\u603b\u7ed3<\/h1>\n\n\n\n
\u76ee\u524d\u6700\u91cd\u8981\u7684\u9519\u8bef\uff1a<\/p>\n\n\n\n
\u6570\u7ec4\n\u251c\u2500 \u8d8a\u754c\n\n\u5b57\u7b26\u4e32\n\u251c\u2500 \\0\n\u251c\u2500 \u7f13\u51b2\u533a\u6ea2\u51fa\n\n\u6307\u9488\n\u251c\u2500 \u672a\u521d\u59cb\u5316\n\u251c\u2500 NULL\n\u251c\u2500 \u60ac\u7a7a\u6307\u9488\n\u2514\u2500 \u9519\u8bef\u89e3\u5f15\u7528\n\n\u52a8\u6001\u5185\u5b58\n\u251c\u2500 \u5fd8\u8bb0 free\n\u251c\u2500 double free\n\u251c\u2500 use-after-free\n\u2514\u2500 realloc \u4f7f\u7528\u4e0d\u5f53\n\n\u7ed3\u6784\u4f53\n\u251c\u2500 . \/ ->\n\u2514\u2500 NULL \u6307\u9488\n\n\u6587\u4ef6\n\u251c\u2500 fopen \u5931\u8d25\n\u251c\u2500 \u5fd8\u8bb0 fclose\n\u2514\u2500 \u6a21\u5f0f\u9519\u8bef\n\n\u591a\u6587\u4ef6\n\u251c\u2500 undefined reference\n\u251c\u2500 \u91cd\u590d\u5b9a\u4e49\n\u2514\u2500 \u58f0\u660e \/ \u5b9a\u4e49\u6df7\u4e71<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u4e94\u5341\u516d\u3001\u4e00\u4e2a\u5b8c\u6574\u7684\u8c03\u8bd5\u6d41\u7a0b<\/h1>\n\n\n\n
\u4ee5\u540e\u9047\u5230 Bug\uff0c\u53ef\u4ee5\u6309\u7167\uff1a<\/p>\n\n\n\n
\u2460 \u8ba9 Bug \u7a33\u5b9a\u590d\u73b0\n        \u2193\n\u2461 \u770b\u7f16\u8bd1\u5668 \/ \u8fd0\u884c\u65f6\u9519\u8bef\n        \u2193\n\u2462 \u786e\u5b9a\u6587\u4ef6\u548c\u4f4d\u7f6e\n        \u2193\n\u2463 \u68c0\u67e5\u8f93\u5165\n        \u2193\n\u2464 \u6253\u5370\u5173\u952e\u53d8\u91cf\n        \u2193\n\u2465 \u68c0\u67e5\u6307\u9488 \/ \u6570\u7ec4\u8fb9\u754c\n        \u2193\n\u2466 \u68c0\u67e5\u5185\u5b58\u751f\u547d\u5468\u671f\n        \u2193\n\u2467 \u4f7f\u7528 GDB \/ Sanitizer\n        \u2193\n\u2468 \u627e\u5230\u771f\u6b63\u539f\u56e0\n        \u2193\n\u2469 \u4fee\u590d\u540e\u91cd\u65b0\u6d4b\u8bd5<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u4e94\u5341\u4e03\u3001\u7efc\u5408\u793a\u4f8b\uff1a\u627e Bug<\/h1>\n\n\n\n
\u4e0b\u9762\u4ee3\u7801\uff1a<\/p>\n\n\n\n
<\/a>#include <\/span><stdio.h><\/span><\/span>\n<\/a>#include <\/span><stdlib.h><\/span><\/span>\n<\/a><\/span>\n<\/a>int<\/span> main()<\/span> {<\/span><\/span>\n<\/a><\/span>\n<\/a>    int<\/span> n =<\/span> 5<\/span>;<\/span><\/span>\n<\/a><\/span>\n<\/a>    int<\/span> *<\/span>arr =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>)<\/span> *<\/span> n);<\/span><\/span>\n<\/a><\/span>\n<\/a>    for<\/span> (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i <=<\/span> n;<\/span> i++)<\/span> {<\/span><\/span>\n<\/a>        arr[<\/span>i]<\/span> =<\/span> i *<\/span> 10<\/span>;<\/span><\/span>\n<\/a>    }<\/span><\/span>\n<\/a><\/span>\n<\/a>    for<\/span> (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i <<\/span> n;<\/span> i++)<\/span> {<\/span><\/span>\n<\/a>        printf(<\/span>\"<\/span>%d<\/span> \"<\/span>,<\/span> arr[<\/span>i]);<\/span><\/span>\n<\/a>    }<\/span><\/span>\n<\/a><\/span>\n<\/a>    free(<\/span>arr);<\/span><\/span>\n<\/a><\/span>\n<\/a>    return<\/span> 0<\/span>;<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u770b\u8d77\u6765\u4f3c\u4e4e\u6ca1\u4ec0\u4e48\u95ee\u9898\u3002<\/p>\n\n\n\n
\u4f46\u662f\uff1a<\/p>\n\n\n\n
<\/a>for<\/span> (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i <=<\/span> n;<\/span> i++)<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8fd9\u91cc\u662f\uff1a<\/p>\n\n\n\n
i <= 5<\/code><\/pre>\n\n\n\n
\u6240\u4ee5\u4f1a\u8bbf\u95ee\uff1a<\/p>\n\n\n\n
arr[5]<\/code><\/pre>\n\n\n\n
\u4f46\u662f\uff1a<\/p>\n\n\n\n
arr<\/code><\/pre>\n\n\n\n
\u53ea\u6709\uff1a<\/p>\n\n\n\n
arr[0]\narr[1]\narr[2]\narr[3]\narr[4]<\/code><\/pre>\n\n\n\n
\u56e0\u6b64\u5e94\u8be5\uff1a<\/p>\n\n\n\n
<\/a>for<\/span> (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i <<\/span> n;<\/span> i++)<\/span> {<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\n\n\n\n
\u4e94\u5341\u516b\u3001\u4f7f\u7528 Sanitizer \u68c0\u67e5<\/h1>\n\n\n\n
\u7f16\u8bd1\uff1a<\/p>\n\n\n\n
<\/a>gcc<\/span> -Wall<\/span> -Wextra<\/span> -g<\/span> \\<\/span><\/span>\n<\/a>    -fsanitize<\/span>=<\/span>address,undefined \\<\/span><\/span>\n<\/a>    main.c -o<\/span> main<\/span><\/code><\/pre><\/div>\n\n\n\n
\u8fd0\u884c\uff1a<\/p>\n\n\n\n
<\/a>.\/main<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
Sanitizer \u5f88\u53ef\u80fd\u4f1a\u62a5\u544a\u7c7b\u4f3c\uff1a<\/p>\n\n\n\n
heap-buffer-overflow<\/code><\/pre>\n\n\n\n
\u5e76\u6307\u51fa\uff1a<\/p>\n\n\n\n
\u54ea\u4e00\u884c\n\u4ec0\u4e48\u8bbf\u95ee<\/code><\/pre>\n\n\n\n
\u8fd9\u6bd4\u5355\u7eaf\u770b\u7a0b\u5e8f\u8f93\u51fa\u66f4\u5bb9\u6613\u53d1\u73b0\u5185\u5b58\u8d8a\u754c\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e94\u5341\u4e5d\u3001\u672c\u7ae0\u6700\u91cd\u8981\u7684\u4e60\u60ef<\/h1>\n\n\n\n
\u4ee5\u540e\u5199 C \u4ee3\u7801\uff0c\u9010\u6e10\u517b\u6210\uff1a<\/p>\n\n\n\n
\u7f16\u8bd1\uff1a\n-Wall -Wextra\n\n\u8c03\u8bd5\uff1a\n-g\n\n\u5185\u5b58\u95ee\u9898\uff1a\n-fsanitize=address,undefined\n\n\u52a8\u6001\u5185\u5b58\uff1a\nmalloc \u2194 free\n\n\u6307\u9488\uff1a\n\u521d\u59cb\u5316\n\n\u6570\u7ec4\uff1a\n\u68c0\u67e5\u8fb9\u754c\n\n\u5b57\u7b26\u4e32\uff1a\n\u9884\u7559 \\0\n\n\u6587\u4ef6\uff1a\nfopen \u2192 \u68c0\u67e5 \u2192 \u4f7f\u7528 \u2192 fclose\n\n\u4ee3\u7801\u4fee\u6539\uff1a\n\u4e00\u6b21\u4e00\u4e2a\u95ee\u9898<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u516d\u5341\u3001\u7ec3\u4e60<\/h1>\n\n\n\n
\u7ec3\u4e60 1<\/h3>\n\n\n\n
\u627e\u51fa\u4e0b\u9762\u4ee3\u7801\u7684\u95ee\u9898\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> arr[<\/span>5<\/span>];<\/span><\/span>\n<\/a><\/span>\n<\/a>for<\/span> (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i <=<\/span> 5<\/span>;<\/span> i++)<\/span> {<\/span><\/span>\n<\/a>    arr[<\/span>i]<\/span> =<\/span> i;<\/span><\/span>\n<\/a>}<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u4fee\u6539\u4e3a\u6b63\u786e\u4ee3\u7801\u3002<\/p>\n\n\n\n
\n\n\n\n
\u7ec3\u4e60 2<\/h3>\n\n\n\n
\u627e\u51fa\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p;<\/span><\/span>\n<\/a><\/span>\n<\/a>*<\/span>p =<\/span> 10<\/span>;<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u7684\u95ee\u9898\u3002<\/p>\n\n\n\n
\u8981\u6c42\u4f7f\u7528\u4e00\u4e2a\u771f\u6b63\u7684\u53d8\u91cf\u8ba9 p<\/code> \u6b63\u786e\u6307\u5411\u5b83\u3002<\/p>\n\n\n\n
\n\n\n\n
\u7ec3\u4e60 3<\/h3>\n\n\n\n
\u4fee\u590d\uff1a<\/p>\n\n\n\n
<\/a>int<\/span> *<\/span>p =<\/span> malloc(<\/span>sizeof<\/span>(<\/span>int<\/span>));<\/span><\/span>\n<\/a><\/span>\n<\/a>*<\/span>p =<\/span> 10<\/span>;<\/span><\/span>\n<\/a><\/span>\n<\/a>free(<\/span>p);<\/span><\/span>\n<\/a><\/span>\n<\/a>printf(<\/span>\"<\/span>%d\\n<\/span>\"<\/span>,<\/span> *<\/span>p);<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u8981\u6c42\u6b63\u786e\u5904\u7406\u91ca\u653e\u540e\u7684\u6307\u9488\u3002<\/p>\n\n\n\n
\n\n\n\n
\u7ec3\u4e60 4<\/h3>\n\n\n\n
\u6545\u610f\u5199\u4e00\u4e2a\uff1a<\/p>\n\n\n\n
\u5185\u5b58\u6cc4\u6f0f<\/code><\/pre>\n\n\n\n
\u7136\u540e\u81ea\u5df1\u4fee\u6539\u6210\u6b63\u786e\u7248\u672c\u3002<\/p>\n\n\n\n
\n\n\n\n
\u7ec3\u4e60 5<\/h3>\n\n\n\n
\u6545\u610f\u5199\u4e00\u4e2a\u6570\u7ec4\u8d8a\u754c\u7a0b\u5e8f\u3002<\/p>\n\n\n\n
\u4f7f\u7528\uff1a<\/p>\n\n\n\n
<\/a>-fsanitize=address<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
\u89c2\u5bdf\u7f16\u8bd1\u8fd0\u884c\u540e\u7684\u9519\u8bef\u62a5\u544a\u3002<\/p>\n\n\n\n
\n\n\n\n
\u7ec3\u4e60 6<\/h3>\n\n\n\n
\u521b\u5efa\uff1a<\/p>\n\n\n\n
main.c\nstudent.c\nstudent.h<\/code><\/pre>\n\n\n\n
\u6545\u610f\u4e0d\u53c2\u4e0e\u7f16\u8bd1\uff1a<\/p>\n\n\n\n
student.c<\/code><\/pre>\n\n\n\n
\u89c2\u5bdf\uff1a<\/p>\n\n\n\n
undefined reference<\/code><\/pre>\n\n\n\n
\u7136\u540e\u4fee\u590d\u3002<\/p>\n\n\n\n
\n\n\n\n
\u7ec3\u4e60 7<\/h3>\n\n\n\n
\u4f7f\u7528 GDB\uff1a<\/p>\n\n\n\n
<\/a>gcc<\/span> -g<\/span> main.c -o<\/span> main<\/span>\n<\/a>gdb<\/span> .\/main<\/span><\/code><\/pre><\/div>\n\n\n\n
\u7ec3\u4e60\uff1a<\/p>\n\n\n\n
break main\nrun\nnext\nprint\ncontinue<\/code><\/pre>\n\n\n\n
\n","protected":false},"excerpt":{"rendered":"
\u524d\u9762\u5df2\u7ecf\u5b66\u4e60\u4e86\uff1a \u5b66\u4e60\u5230\u8fd9\u91cc\uff0c\u4ee3\u7801\u5f00\u59cb\u53d8\u590d\u6742\u3002 \u4e8e\u662f\u4f1a\u7ecf\u5e38\u9047\u5230\uff1a \u8fd9\u65f6\u5019\u6700\u91cd\u8981\u7684\u4e0d\u662f\uff1a \u800c\u662f\u5b66\u4f1a\uff1a \u5b9a\u4f4d\u95ee\u9898\u3002 \u4e00\u3001\u4ec0\u4e48\u662f Bug …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"emotion":"","emotion_color":"","title_style":"","license":"","footnotes":""},"categories":[1],"tags":[],"class_list":["post-106","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/decagrammaton.xyz\/index.php?rest_route=\/wp\/v2\/posts\/106","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/decagrammaton.xyz\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/decagrammaton.xyz\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/decagrammaton.xyz\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/decagrammaton.xyz\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=106"}],"version-history":[{"count":3,"href":"https:\/\/decagrammaton.xyz\/index.php?rest_route=\/wp\/v2\/posts\/106\/revisions"}],"predecessor-version":[{"id":109,"href":"https:\/\/decagrammaton.xyz\/index.php?rest_route=\/wp\/v2\/posts\/106\/revisions\/109"}],"wp:attachment":[{"href":"https:\/\/decagrammaton.xyz\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=106"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/decagrammaton.xyz\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=106"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/decagrammaton.xyz\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=106"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}