Get DLL path at runtime

Yochai Timmer picture Yochai Timmer · Aug 3, 2011 · Viewed 68.5k times · Source

I want to get a dll's directory (or file) path from within its code. (not the program's .exe file path)

I've tried a few methods I've found:
GetCurrentDir - gets the current directory path.
GetModuleFileName - gets the executable's path.

So how can i find out in which dll the code is in ?
I'm looking for something similar to C#'s Assembly.GetExecutingAssembly

Answer

mkaes picture mkaes · Aug 3, 2011

You can use the GetModuleHandleEx function and get the handle to a static function in your DLL. You'll find more information here.

After that you can use GetModuleFileName to get the path from the handle you just obtained. More information on that call is here.

A complete example:

char path[MAX_PATH];
HMODULE hm = NULL;

if (GetModuleHandleEx(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS | 
        GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
        (LPCSTR) &functionInThisDll, &hm) == 0)
{
    int ret = GetLastError();
    fprintf(stderr, "GetModuleHandle failed, error = %d\n", ret);
    // Return or however you want to handle an error.
}
if (GetModuleFileName(hm, path, sizeof(path)) == 0)
{
    int ret = GetLastError();
    fprintf(stderr, "GetModuleFileName failed, error = %d\n", ret);
    // Return or however you want to handle an error.
}

// The path variable should now contain the full filepath for this DLL.