本文介绍了在本地代码中使用Windows环境变量的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
$ _ code> //我有权创建一个文件到程序文件const std :: wstring sFileName = L%ProgramFiles%\\\aaaa。
HANDLE h = CreateFileW(
sFileName.c_str(),
GENERIC_READ,
FILE_SHARE_DELETE,
0,
CREATE_ALWAYS,
0,
0);
// INVALID_HANDLE_VALUE with ERROR_PATH_NOT_FOUND
我预计它会使 C:\Program Files \aaa.txt 或 C:\Program文件(x86)\aaa.txt 取决于Os的环境。但它没有工作。
怎么了?如何在本地代码中使用环境变量?
解决方案
您需要显式扩展环境变量。一种方法是使用Win32 API的ExpandEnvironmentStrings或ExpandEnvironmentStringsForUser
请参阅:
// I have a permission to create a file to Program Files
const std::wstring sFileName = L"%ProgramFiles%\\aaa.txt";
HANDLE h = CreateFileW(
sFileName.c_str(),
GENERIC_READ,
FILE_SHARE_DELETE,
0,
CREATE_ALWAYS,
0,
0);
// INVALID_HANDLE_VALUE with ERROR_PATH_NOT_FOUND
I expected it makes C:\Program Files\aaa.txt or C:\Program Files (x86)\aaa.txt depend on the Os' environment. But it didn't work.
What's wrong? How do I use environment variable in native code?
解决方案
You need to explicitly expand the environment variables. One way is using the Win32 API's ExpandEnvironmentStrings or ExpandEnvironmentStringsForUser
See:
http://msdn.microsoft.com/en-us/library/ms724265(v=vs.85).aspx
http://msdn.microsoft.com/en-us/library/bb762275(v=vs.85).aspx
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