How to get the %AppData% folder in C?

Question

As above, how do I get the AppData folder in Windows using C?

I know that for C# you use Environment.SpecialFolder.ApplicationData

Answer 1

Use SHGetSpecialFolderPath with a CSIDL set to the desired folder (probably CSIDL_APPDATA or CSIDL_LOCAL_APPDATA).

You can also use the newer SHGetFolderPath() and SHGetKnownFolderPath() functions. There's also SHGetKnownFolderIDList() and if you like COM there's IKnownFolder::GetPath().

Answer 2

If I recall correctly it should just be

#include <stdlib.h>
getenv("APPDATA");

Edit: Just double-checked, works fine!

Answer 3

Using the %APPDATA% environment variable will probably work most of the time. However, if you want to do this the official Windows way, you should use use the SHGetFolderPath function, passing the CSIDL value CSIDL_APPDATA or CSIDL_LOCAL_APPDATA, depending on your needs.

This is what the Environment.GetFolderPath() method is using in .NET.

EDIT: Joey correctly points out that this has been replaced by SHGetKnownFolderPath in Windows Vista. News to me :-).

Answer 4

You might use these functions:

#include <stdlib.h>
char *getenv( 
   const char *varname 
);
wchar_t *_wgetenv( 
   const wchar_t *varname 
);

Like so:

#include <stdio.h>
char *appData = getenv("AppData");
printf("%s\n", appData);

Answer 5

Sample code:

TCHAR szPath[MAX_PATH];
if (SUCCEEDED(SHGetFolderPath(NULL,
   CSIDL_APPDATA | CSIDL_FLAG_CREATE,
   NULL,
   0,
   szPath)))
{
   PathAppend(szPath, TEXT("MySettings.xml"));
   HANDLE hFile = CreateFile(szPath, ...);
}

CSIDL_APPDATA = username\Application Data. In Window 10 is: username\AppData\Roaming

CSIDL_FLAG_CREATE = combine with CSIDL_ value to force folder creation in SHGetFolderPath()

You can also use:

CSIDL_LOCAL_APPDATA = username\Local Settings\Application Data (non roaming)