作者：朱金灿
来源：http://blog.csdn.net/clever101/

最近正在学习osg，从osgchina网站下下载了osg的debug版本库，具体地址为：

OpenSceneGraph-2.8.2预编译包（for vs9）下载

然后建了一个MFC的单文档程序写一些测试代码，调试运行了一下，退出时出现大量的内存泄露：
......
{184} normal block at 0x00FB7510, 24 bytes long.
Data: < u u u > 10 75 FB 00 10 75 FB 00 10 75 FB 00 CD CD CD CD
{183} normal block at 0x00FB7150, 896 bytes long.
Data: < > 00 00 00 00 CD CD CD CD CD CD CD CD CD CD CD CD
{181} normal block at 0x00FB70A0, 24 bytes long.
Data: < a > D8 61 15 00 FF FF FF FF 00 00 00 00 00 00 00 00
{180} normal block at 0x00FB6FE0, 128 bytes long.
Data: < > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
{179} normal block at 0x00FB6F20, 128 bytes long.
Data: < > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
{178} normal block at 0x00FB6E60, 128 bytes long.
Data: < > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
{137} normal block at 0x00FB6D98, 136 bytes long.
Data: < WC > D8 57 43 10 00 00 00 00 01 00 00 00 00 00 00 00
{135} normal block at 0x00FB6C58, 64 bytes long.
Data: <OpenThread v1.2p> 4F 70 65 6E 54 68 72 65 61 64 20 76 31 2E 32 70

开始我吃了一惊，上网搜了一下，找到了一个解决办法：

Why does my OSG MFC based application show memory leaks

这个网页上给出的解决办法是：

. Goto project settings. In there, make the following changes for theDebug build.
. General->Use of MFC->Use Standard Windows Libraries.
. Add _AFXDLL to C/C++->Preprocessor->Preprocessor Definitions.
. Add mfc80??.lib (in my case it is mfc80ud.lib) as a first dependency or at least before osg libs to Linker->Input->Additional
Dependencies.

我按照这个办法一试，出现了一个链接错误：
1>msvcrtd.lib(crtexew.obj) : error LNK2019: unresolved external symbol _WinMain@16 referenced in function ___tmainCRTStartup
1>E:/OSG Play/Debug/osgSdi.exe : fatal error LNK1120: 1 unresolved externals
1>Build log was saved at "file://e:/OSG Play/osgSdi/Debug/BuildLog.htm"
1> osgSdi - 2 error(s), 0 warning(s)

之前我只是添加了附加库mfc90ud.lib，这下我把msvcrtd.lib也加进去了，发现还是有这个错误。于是搜索了一下"error LNK2019: unresolved external symbol _WinMain@16 referenced in function ___tmainCRTStartup"，判断可能是使用字符集不当造成的。于是在选项里使用多字节字符集，附加库使用mfc90d.lib。重新编译之后好了，我想是不是因为我的osg的核心库是基于多字节字符集生成而造成这个问题的呢？或许只有用unicode版本的osg库一试才能知道。

早上起来，想到了一个测试办法，就是建一个单文档程序，采用unicode字符集编译，附加库添加mfc90ud.lib，发现也会出现error LNK2019: unresolved external symbol _WinMain@16 referenced in function ___tmainCRTStartup的错误，但采用多字节字符集没有问题。看来并不是osg库的问题。