Informs the data link service (DLS) user that a request or response was invalid.
The message consists of one M_PCPROTO message block, which contains the following structure:
typedef struct 
{
   ulong  dl_primitive;
   ulong  dl_error_primitive;
   ulong  dl_errno;
   ulong  dl_unix_errno;
} dl_ok_ack_t;
This structure is defined in /usr/include/sys/dlpi.h.
The DL_ERROR_ACK primitive informs the DLS user that the previously issued request or response was invalid. This primitive identifies the primitive in error, specifies a Data Link Provider Interface (DLPI) error code, and if appropriate, indicates an operating system error code.
| Item | Description | 
|---|---|
| dl_primitive | Specifies the DL_ERROR_ACK primitive. | 
| dl_error_primitive | Identifies the primitive that caused the error. | 
| dl_errno |   Specifies the DLPI error code associated with the failure.
See the individual request or response for the error codes that are
applicable. In addition to those errors:  
  | 
| dl_unix_errno | Specifies the operating system error code associated with the failure. This value should be nonzero only when the dl_errno parameter is set to DL_SYSERR. It is used to report operating system failures that prevent the processing of a given request or response. | 
| Item | Description | 
|---|---|
| Valid | The primitive is valid in all states that have a pending acknowledgment or confirmation. | 
| New | The resulting state is the same as the one from which the acknowledged request or response was generated. |