NAME
        CreateExtIO -- create an iorequest structure

   SYNOPSIS
        ioReq = CreateExtIO(port,ioSize);

        struct iorequest *createextio(struct msgport *, ulong);

   FUNCTION
        Allocates memory for and initializes a new IO request block
        of a user-specified number of bytes. The number of bytes
        MUST be the size of a legal iorequest (or extended iorequest)
        or very nasty things will happen.

   INPUTS
        port - an already initialized message port to be used for this IO
               request's reply port. If this is NULL this function fails.
        ioSize - the size of the IO request to be created.

   RESULT
        ioReq - a new IO request block, or null if there was not enough memory

   EXAMPLE
        if (ioReq = CreateExtIO(CreatePort(NULL,0),sizeof(struct IOExtTD)))

   SEE ALSO
        deleteextio(), createport(), exec.library/createmsgport()