Thread: Expanding Environment Variables

I am trying to get the path of the system root directory by using %SystemRoot% in C code. What I originally had was:

Code:

TCHAR szBuf[1024];
wsprintf(szBuf, L"c:\\windows\\system32\\myapp.exe \r\n");
WriteLogFile(szBuf);

Now, I want to grab the system root directory at runtime and use that instead of hardcoding in the location as on win2k, the path is "c:\winnt" or people may have installed their os on a different drive.

I know in c++ or in c# you can use the Environment.ExpandEnvironmentVariables Method.

Code:

String query = "My system drive is %SystemDrive% and my system root is %SystemRoot%";
String  str = Environment.ExpandEnvironmentVariables(query);

This will give an output of something like: "My system drive is C: and my system root is C:\WINNT"

Is there something similar in c that I can use?

http://msdn2.microsoft.com/en-us/library/ms724373.aspx

Thanks for the suggestions! I was able to get it working like so...

Code:

TCHAR szBuf[1024];
TCHAR szMyApp[1024];
wchar_t systemrootpath[64]= L"";
wchar_t dname[64]=L"";

...

wsprintf(szBuf, L"%s", getenv("SystemRoot"));
mbstowcs(systemrootpath, szBuf, 64);  // Convert to unicode

wsprintf(szMyApp,L"%s\\system32\\myapp.exe %s\0", systemrootpath, dname);

...