今天写一个demo，编译的时候发现编不过，错误如下：
1>------ Build started: Project: KuanLibTest, Configuration: Release Win32 ------
1>Compiling...
1>stdafx.cpp
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(21) : error C2039: 'div_t' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(21) : error C2873: 'div_t' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(21) : error C2039: 'ldiv_t' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(21) : error C2873: 'ldiv_t' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(23) : error C2039: 'abort' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(23) : error C2873: 'abort' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(23) : error C2039: 'abs' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(23) : error C2873: 'abs' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(24) : error C2039: 'atof' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(24) : error C2873: 'atof' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(24) : error C2039: 'atoi' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(24) : error C2873: 'atoi' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(24) : error C2039: 'atol' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(24) : error C2873: 'atol' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(25) : error C2039: 'bsearch' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(25) : error C2873: 'bsearch' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(25) : error C2039: 'calloc' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(25) : error C2873: 'calloc' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(25) : error C2039: 'div' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(25) : error C2873: 'div' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(26) : error C2039: 'exit' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(26) : error C2873: 'exit' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(26) : error C2039: 'free' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(26) : error C2873: 'free' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(26) : error C2039: 'getenv' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(26) : error C2873: 'getenv' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(27) : error C2039: 'labs' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(27) : error C2873: 'labs' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(27) : error C2039: 'ldiv' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(27) : error C2873: 'ldiv' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(27) : error C2039: 'malloc' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(27) : error C2873: 'malloc' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(28) : error C2039: 'mblen' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(28) : error C2873: 'mblen' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(28) : error C2039: 'mbstowcs' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(28) : error C2873: 'mbstowcs' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(28) : error C2039: 'mbtowc' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(28) : error C2873: 'mbtowc' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(29) : error C2039: 'qsort' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(29) : error C2873: 'qsort' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(29) : error C2039: 'rand' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(29) : error C2873: 'rand' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(29) : error C2039: 'realloc' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(29) : error C2873: 'realloc' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(30) : error C2039: 'srand' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(30) : error C2873: 'srand' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(30) : error C2039: 'strtod' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(30) : error C2873: 'strtod' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(30) : error C2039: 'strtol' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(30) : error C2873: 'strtol' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(31) : error C2039: 'strtoul' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(31) : error C2873: 'strtoul' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(31) : error C2039: 'system' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(31) : error C2873: 'system' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(32) : error C2039: 'wcstombs' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(32) : error C2873: 'wcstombs' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(32) : error C2039: 'wctomb' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstdlib(32) : error C2873: 'wctomb' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(19) : error C2039: 'memchr' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(19) : error C2873: 'memchr' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(19) : error C2039: 'memcmp' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(19) : error C2873: 'memcmp' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(21) : error C2039: 'memset' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(21) : error C2873: 'memset' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(22) : error C2039: 'strcat' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(22) : error C2873: 'strcat' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(22) : error C2039: 'strchr' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(22) : error C2873: 'strchr' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(22) : error C2039: 'strcmp' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(22) : error C2873: 'strcmp' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(23) : error C2039: 'strcoll' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(23) : error C2873: 'strcoll' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(23) : error C2039: 'strcpy' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(23) : error C2873: 'strcpy' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(23) : error C2039: 'strcspn' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(23) : error C2873: 'strcspn' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(24) : error C2039: 'strerror' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(24) : error C2873: 'strerror' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(24) : error C2039: 'strlen' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(24) : error C2873: 'strlen' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(24) : error C2039: 'strncat' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(24) : error C2873: 'strncat' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(25) : error C2039: 'strncmp' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(25) : error C2873: 'strncmp' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(25) : error C2039: 'strncpy' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(25) : error C2873: 'strncpy' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(25) : error C2039: 'strpbrk' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(25) : error C2873: 'strpbrk' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(26) : error C2039: 'strrchr' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(26) : error C2873: 'strrchr' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(26) : error C2039: 'strspn' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(26) : error C2873: 'strspn' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(26) : error C2039: 'strstr' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(26) : error C2873: 'strstr' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(27) : error C2039: 'strtok' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(27) : error C2873: 'strtok' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(27) : error C2039: 'strxfrm' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\cstring(27) : error C2873: 'strxfrm' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\exception(208) : error C2039: 'set_terminate' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\exception(208) : error C2873: 'set_terminate' : symbol cannot be used in a using-declaration
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\exception(208) : error C2039: 'terminate_handler' : is not a member of '`global namespace''
1>E:\Program Files\Microsoft Visual Studio 9.0\VC\include\exception(208) : fatal error C1003: error count exceeds 100; stopping compilation
1>Build log was saved at "file://f:\Live Mesh\computer\Coding\fangyukuan\trunk\cpp\kuanlib_test\KuanLibTest\Release\BuildLog.htm"
1>KuanLibTest - 102 error(s), 0 warning(s)
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
后来发现，是我把 #include <string> 放到命名空间里了。而string包含了cstdlib这个文件。所以里面的函数被限制到这个命名空间了。而其它地方用的时候，没有使用这个命名空间，导致上面的编译错误。这些只是我的推测。
我把#include <string>和其它包含路径移到命名空间外面，就编译通过了。
以后要记住：不要把包含的路径放到命名空间里。
当然如果是想把某个头文件里的定义限制在某个命名空间的时候，可以把包含听路径放到命名空间里。其实有时我解决命名冲突也用这种方法的。
本文地址：http://www.cnblogs.com/fangyukuan/archive/2010/06/17/1759757.html