C++與MySQL的沖突

當在C++代碼中，直接引用MySQL頭檔案時，可能會遇到如下錯誤：

In file included from /usr/include/c++/4.1.0/bits/char_traits.h:46,

                 from /usr/include/c++/4.1.0/string:46,

/usr/include/c++/4.1.0/bits/stl_algobase.h:92:28: error: macro "swap" requires 3 arguments, but only 2 given

/usr/include/c++/4.1.0/bits/stl_algobase.h:127:26: error: macro "swap" requires 3 arguments, but only 2 given

/usr/include/c++/4.1.0/bits/vector.tcc:176:20: error: macro "swap" requires 3 arguments, but only 1 given

/usr/include/c++/4.1.0/cctype:70: error: '::isalnum' has not been declared

/usr/include/c++/4.1.0/cctype:71: error: '::isalpha' has not been declared

/usr/include/c++/4.1.0/cctype:72: error: '::iscntrl' has not been declared

/usr/include/c++/4.1.0/cctype:73: error: '::isdigit' has not been declared

/usr/include/c++/4.1.0/cctype:74: error: '::isgraph' has not been declared

/usr/include/c++/4.1.0/cctype:75: error: '::islower' has not been declared

/usr/include/c++/4.1.0/cctype:76: error: '::isprint' has not been declared

/usr/include/c++/4.1.0/cctype:77: error: '::ispunct' has not been declared

/usr/include/c++/4.1.0/cctype:78: error: '::isspace' has not been declared

/usr/include/c++/4.1.0/cctype:79: error: '::isupper' has not been declared

/usr/include/c++/4.1.0/cctype:80: error: '::isxdigit' has not been declared

/usr/include/c++/4.1.0/cctype:81: error: '::tolower' has not been declared

/usr/include/c++/4.1.0/cctype:82: error: '::toupper' has not been declared

解決辦法：

盡量對MySQL進行二次包裝，讓調用者看不到MySQL頭檔案，如在CPP中包含：

#include <my_global.h>

#include <my_sys.h>

#include <mysql.h>

在頭檔案中隻進行引用聲明：

struct st_mysql;

struct st_mysql_res;

typedef long num_t;

typedef char ** MYSQL_ROW;  /** return data as array of strings */

不要在頭檔案直接include到MySQL的頭檔案，而且保證隻在一個CPP檔案中有對MySQL檔案的include，否則你可能遇到很多莫名其妙的編譯錯誤，如果不想到這一點，即使花一天時間也未必能找到錯誤原因。

補充：

MySQL4.x和MySQL5.x頭檔案不相容的，最好使用5.x版本

有些版本隻能引用#include <mysql.h>，包含其它會報C++标準庫中某檔案錯誤。

原帖發在我的論壇：

<a href="http://bbs.hadoopor.com/thread-1564-1-1.html">http://bbs.hadoopor.com/thread-1564-1-1.html</a>

    本文轉自eyjian 51CTO部落格，原文連結：http://blog.51cto.com/mooon/909758，如需轉載請自行聯系原作者