- 1 year ago
CreateFile with FILE_FLAG_NO_BUFFERING but not FILE_FLAG_WRITE_THROUGH
When working with the CreateFile
function in Windows, you can use the FILE_FLAG_NO_BUFFERING
flag to perform direct I/O, bypassing the system's cache and working directly with the storage device. However, combining this flag with FILE_FLAG_WRITE_THROUGH
can lead to unexpected behavior or errors.
If you need to perform direct I/O without enabling write-through mode, you can omit the FILE_FLAG_WRITE_THROUGH
flag and still achieve the desired behavior. When you use FILE_FLAG_NO_BUFFERING
without FILE_FLAG_WRITE_THROUGH
, the data will be written directly to the storage device, but the system cache will still be used for read operations.
Here's an example of how you can use CreateFile
with FILE_FLAG_NO_BUFFERING
but not FILE_FLAG_WRITE_THROUGH
:
gopackage main
import (
"fmt"
"os"
"syscall"
)
func main() {
// Replace "path/to/your/file" with the actual path of the file you want to open
filePath := "path/to/your/file"
// Open the file with the desired flags and attributes
handle, err := syscall.CreateFile(syscall.StringToUTF16Ptr(filePath),
syscall.GENERIC_READ|syscall.GENERIC_WRITE,
0,
nil,
syscall.OPEN_EXISTING,
syscall.FILE_FLAG_NO_BUFFERING,
0)
if err != nil {
fmt.Printf("Error opening file: %s\n", err)
return
}
defer syscall.CloseHandle(handle)
// Perform read and write operations directly on the handle, without using the system cache
// ...
}
Please note that using direct I/O with FILE_FLAG_NO_BUFFERING
can have some specific requirements and limitations, such as alignment and size constraints. It is essential to carefully consider the implications and thoroughly test your code to ensure correct behavior and performance.