當在C 代碼中，直接引用MySQL頭文件時，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頭文件，如在CPP中包含：
#include <my_global.h>
#include <my_sys.h>
#include <mysql.h>
在頭文件中只進行引用聲明：
struct st_mysql;
struct st_mysql_res;
typedef long num_t;
typedef char ** MYSQL_ROW; /** return data as array of strings */
不要在頭文件直接include到MySQL的頭文件，而且保證只在一個CPP文件中有對MySQL文件的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頭文件不兼容的，最好使用5.x版本
補充： 有些版本只能引用#include <mysql.h>，包含其它會報C 標准庫中某文件錯誤。
