Question

I made a screen saver in C that uses SDL. I put it in System32 along with the folder of pictures it uses and SDL.dll but I get an error when I try to run it. It can’t find SDL.dll! It works in any other folder with SDL.dll in it. Why not System32? I’m not even trying to run it as a screen saver. When I right click it and hit “Test” it says it can’t find SDL.dll. What is wrong? What should I do?

Answer 1

Put SDL.dll somewhere on the PATH. Windows needs to be able to find it, and it doesn’t know to look in the folder you created.

You can tell how Windows looks for DLLs by reading the documentation for LoadLibrary:

The first directory searched is the directory containing the image
file used to create the calling process (for more information, see the
CreateProcess function). Doing this allows private dynamic-link
library (DLL) files associated with a process to be found without
adding the process’s installed directory to the PATH environment
variable. If a relative path is specified, the entire relative path is
appended to every token in the DLL search path list. To load a module
from a relative path without searching any other path, use
GetFullPathName to get a nonrelative path and call LoadLibrary with
the nonrelative path. For more information on the DLL search order,
see Dynamic-Link Library Search Order.