getq(D3)

NAME
     getq - get the next message from a queue

SYNOPSIS
     #include <sys/stream.h>
     #include <sys/ddi.h>
     mblk_t *getq(queue_t *q);

   Arguments
     q         Pointer to the queue from which the message is to be retrieved.

DESCRIPTION
     getq gets the next available message from the top of the queue pointed to
     by q.  It handles flow control, restarting I/O that was blocked as
     needed.

   Return Values
     If there is a message to retrieve, getq returns a pointer to it.  If no
     message is queued, getq returns a NULL pointer.

USAGE
     getq is typically used by service routines [see srv(D2)] to retrieve
     queued messages.

   Level
     Base or Interrupt.

   Synchronization Constraints
     Does not sleep.

     Driver-defined basic locks, read/write locks, and sleep locks may be held
     across calls to this function.

   Examples
     See srv(D2) for an example of getq.

REFERENCES
     bcanput(D3), canput(D3), putbq(D3), putq(D3), qenable(D3), rmvq(D3),
     srv(D2)