phalloc(D3)

NAME
     phalloc - allocate and initialize a pollhead structure

SYNOPSIS
     #include <sys/poll.h>
     #include <sys/kmem.h>
     #include <sys/ddi.h>
     struct pollhead *phalloc(int flag);

   Arguments
     flag      Specifies whether the caller is willing to sleep waiting for
               memory.

DESCRIPTION
     phalloc allocates and initializes a pollhead structure for use by non-
     STREAMS character drivers that wish to support polling.  If flag is set
     to KM_SLEEP, the caller will sleep if necessary until sufficient memory
     is available.  If flag is set to KM_NOSLEEP, the caller will not sleep,
     but phalloc will return NULL if sufficient memory is not immediately
     available.

   Return Values
     On success, phalloc returns a pointer to the newly allocated pollhead
     structure.  If KM_NOSLEEP is specified and sufficient memory is not
     immediately available, phalloc returns a NULL pointer.

USAGE
     On systems where the phalloc function is available, DDI/DKI conforming
     drivers should only use pollhead structures which have been allocated and
     initialized using phalloc.  Use of pollhead structures which have been
     obtained by any other means is prohibited on such systems.

   Level
     Base only if flag is set to KM_SLEEP.

     Initialization, Base or Interrupt if flag is set to KM_NOSLEEP.

   Synchronization Constraints
     May sleep if flag is set to KM_SLEEP.

     Driver-defined basic locks and read/write locks may be held across calls
     to this function if flag is KM_NOSLEEP but may not be held if flag is
     KM_SLEEP.

     Driver-defined sleep locks may be held across calls to this function
     regardless of the value of flag.

REFERENCES
     poll(D2), phfree(D3)