How to test for file locks on Windows in golang

22 Oct 2015

I needed a way to test if a file was still locked by another process. I ended up creating the function below. It uses the windows.Open function that eventually calls the win api function CreateFile. I try to get the Read/Write, Create and Append permission for the file. If another process is using that file it will fail and return an error, otherwise it will return a file handle that will be closed using windows.Close.

import "golang.org/x/sys/windows"
func IsFileLocked(path string) bool {
ret := false
f, err := windows.Open(path, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
if err != nil {
fmt.Println(“File is locked”, err)
ret = true
}
windows.Close(f)
return ret
}