3 ms·

"is executable" is different from "is an executable". Your other comment was worded to say the former, while this one seems to refer to the latter. For example

"is executable" is different from "is an executable". Your other comment was worded to say the former, while this one seems to refer to the latter. For example, a .jpg image can be marked as executable, but it is not an executable. This can happen on both Linux and Windows, and I believe it is handled by the filesystem. I supposed the term "marked as executable" could be used for this, while "is executable" could mean the OS will grant it a PID using the correct system call, but this is uncommon. On Linux, you can attempt to execute any file using a system call like execve(). Similarly, on Windows you can also attempt to run a JPEG using CreateProcess(). I know the Windows shell probably won't run a JPEG even if it is marked executable(there are a collection of Registry entries that map file extensions to programs that run them, for the shell), but I don't know if the CreateProcess() API function rejects files without the correct extension. If both CreateProcess() and GetBinaryType() fail to detect a PE file with the incorrect extension, then you can reasonably say that Windows uses the extension to determine whether a file is an executable(though not whether it is executable). The behavior of the shell isn't sufficient.

Stratoscope 10y ago
CreateProcess() doesn't care what the file extension is when you pass the executable filename into the lpApplicationName parameter. I used this feature when I worked on a VR app written in Unity, and I had a little launcher program that checked for updates and then started the main program. I didn't want people to bypass the launcher, so I renamed the main program to have a .VR extension instead of .exe, preventing it from being run directly from File Explorer. The launcher had a .exe extension and could be run normally, and then it used CreateProcess to run the FooBar.VR executable.

Stratoscope 10y ago

CreateProcess() doesn't care what the file extension is when you pass the executable filename into the lpApplicationName parameter. I used this feature when I worked on a VR app written in Unity, and I had a little launcher program that checked for updates and then started the main program. I didn't want people to bypass the launcher, so I renamed the main program to have a .VR extension instead of .exe, preventing it from being run directly from File Explorer. The launcher had a .exe extension and could be run normally, and then it used CreateProcess to run the FooBar.VR executable.