PxMsgGetProtection()

Get protection mode of a message.

APPLIES TO

8.2.0

SYNOPSIS

PxAccessPerm_t PxMsgGetProtection (PxMsg_t msgid);

ARGUMENTS

msgid: Message object for which the protection mode is requested

RETURN VALUES

Protection mode (NoAccessProtection, ReadProtection, WriteProtection, WRProtection)

ERROR CODES

PXERR_MSG_ILLMSG

msgid is not a valid object id

PXERR_MSG_ILLUSER

The calling task is not user of this message

DESCRIPTION

PxMsgGetProtection returns the protection mode for the data area of a given message object msgid. The following values are possible:

NoAccessProtection the caller has no access to the messages data area
ReadProtection the caller has read only access to the messages data area
WriteProtection the caller has write only access to the messages data area
WRProtection the caller has read and write access to the messages data area

IMPLEMENTATION GUIDELINES

Before call

msgid must be a valid message object, requested via PxMsgRequest… or PxMsgEnvelop… or received by a PxMsgReceive… call (V). This id may be checked with one of the following macros:
- PxMsgIdIsValid() must be true.
- PxMsgIdGet() must not be _PXIllegalObjId.
- PxMsgIdError() must be PXERR_NOERROR otherwise the returned error code has to be interpreted (C).

After call

PxMsgGetProtection returns a value of type PxProtectType_t, which may have one of the following values (V):
- NoAccessProtection neither read nor write access
- ReadProtection read access
- WriteProtection write access
- WRProtection read and write access

Best Practice

No restrictions.

SEE ALSO

PxMsgEnvelop()

USAGE

#include "pxdef.h"

PxProtectType_t protType = PxMsgGetProtection(msgid);
switch (protType)
{
case NoAccessProtection:
	// Task has no permission to access message data
	break;
case ReadProtection:
	// Task has read-only permission to access message data
	break;
case WriteProtection:
	// Task has write-only permission to access message data
	break;
case WRProtection:
	// Task has read and write permission to access message data
	break;
}