UDK2018写EFI程序时，gEfiShellProtocol为什么locate不到？

Question

我在写UEFI APP时，想要调用gEfiShellProtocol的getEnv和setEnv的成员函数，
但是发现gEfiShellProtocol一直为NULL，请问这个要怎么解决?

    if (gEfiShellProtocol == NULL) {
        //
        // Search for the shell protocol
        //
        Status = gBS->LocateProtocol (
          &gEfiShellProtocolGuid,
          NULL,
          (VOID **)&gEfiShellProtocol
        );
        if (EFI_ERROR (Status)) {
          gEfiShellProtocol = NULL;
        }
      }

Answer 1

https://blog.csdn.net/u011617231/article/details/81840954