MySQL C API内存泄漏？

Question

最近，我开始编写一个使用 libmysqlclient 的 C 程序。使用 valgrind 检查我的代码时，它报告内存泄漏。以下最小代码片段重现了该行为:

#include <mysql.h>

int main(void)
{
    MYSQL* mysql = mysql_init(0);

    mysql_close(mysql);

    return 0;
}

用 valgrind 检查生成的程序告诉我:

==25614== LEAK SUMMARY:
==25614==    definitely lost: 0 bytes in 0 blocks
==25614==    indirectly lost: 0 bytes in 0 blocks
==25614==      possibly lost: 0 bytes in 0 blocks
==25614==    still reachable: 288 bytes in 3 blocks
==25614==         suppressed: 0 bytes in 0 blocks

根据 MySQL API 引用，mysql_close()...

Closes a previously opened connection. mysql_close() also deallocates the connection handle pointed to by mysql if the handle was allocated automatically by mysql_init() or mysql_connect().

但是，valgrind 报告未释放的内存。这里有什么问题吗？

Answer 1

通过深入研究文档，我找到了解决问题的函数 mysql_library_end()。

引自 MySQL API 引用:

This function finalizes the MySQL library. You should call it when you are done using the library (for example, after disconnecting from the server).

就我个人而言，我发现 libmysqlclient 强制其用户调用其自己的清理函数非常烦人。 IMO，一个更好的解决方案是在连接计数降为零时自动调用 mysql_library_end()。