Checks to see if a message is marked.
The I_ATMARK operation shows the user if the current message on the stream-head read queue is marked by a downstream module. The arg parameter determines how the checking is done when there are multiple marked messages on the stream-head read queue. The possible values for the arg parameter are:
Value | Description |
---|---|
ANYMARK | Read to determine if the message is marked by a downstream module. |
LASTMARK | Read to determine if the message is the last one marked on the queue by a downstream module. |
The I_ATMARK operation returns a value of 1 if the mark condition is satisfied. Otherwise, it returns a value of 0.
This operation is part of STREAMS Kernel Extensions.
If unsuccessful, the errno global variable is set to the following value:
Value | Description |
---|---|
EINVAL | The value of the arg parameter could not be used. |