msgdsize(D3)

NAME
     msgdsize - return number of bytes of data in a message

SYNOPSIS
     #include <sys/stream.h>
     #include <sys/ddi.h>
     int msgdsize(mblk_t *mp);

   Arguments
     mp        Pointer to the message to be evaluated.

DESCRIPTION
     msgdsize counts the number of bytes of data in the message pointed to by
     mp.  Only bytes included in message blocks of type M_DATA are included in
     the count.

   Return Values
     The number of bytes of data in the message.

USAGE
   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 insq(D3) for an example of msgdsize.

REFERENCES
     msgb(D4)