ddi_mmap_get_model(9F)					   Kernel Functions for Drivers 				    ddi_mmap_get_model(9F)

NAME

       ddi_mmap_get_model - return data model type of current thread

SYNOPSIS

       #include <sys/ddi.h>
       #include <sys/sunddi.h>

       uint_t ddi_mmap_get_model(void);

INTERFACE LEVEL

       Solaris DDI specific (Solaris DDI).

DESCRIPTION

       ddi_mmap_get_model()  returns  the C Language Type Model which the current thread expects. ddi_mmap_get_model() is used in combination with
       ddi_model_convert_from(9F) in the mmap(9E) driver entry point to determine whether there is a  data  model  mismatch  between  the  current
       thread  and  the  device driver. The device driver might have to adjust the shape of data structures before exporting them to a user thread
       which supports a different data model.

RETURN VALUES

       "small and bold">DDI_MODCurrent2thread expects 32-bit (ILP32) semantics.

       DDI_MODEL_LP64	       Current thread expects 64-bit (LP64) semantics.

       DDI_FAILURE	       The ddi_mmap_get_model() function was not called from the mmap(9E) entry point.

CONTEXT

       The ddi_mmap_get_model() function can only be called from the mmap(9E) driver entry point.

EXAMPLES

       Example 1: : Using ddi_mmap_get_model()

       The following is an example of the mmap(9E) entry point and how to support 32-bit and 64-bit applications with the same device driver.

       struct data32 {
	       int len;
	       caddr32_t addr;
       };

       struct data {
	       int len;
	       caddr_t addr;
       };
       xxmmap(dev_t dev, off_t off, int prot) {
	       struct data dtc; /* a local copy for clash resolution */
	       struct data *dp = (struct data *)shared_area;

	       switch (ddi_model_convert_from(ddi_mmap_get_model())) {
	       case DDI_MODEL_ILP32:
	       {
		       struct data32 *da32p;

		       da32p = (struct data32 *)shared_area;
		       dp = &dtc;
		       dp->len = da32p->len;
		       dp->address = da32->address;
		       break;
	       }
	       case DDI_MODEL_NONE:
		       break;
	       }
	       /* continues along using dp */
	      ...
       }

SEE ALSO

       mmap(9E), ddi_model_convert_from(9F)

       Writing Device Drivers

SunOS 5.10							    8 Feb 2001						    ddi_mmap_get_model(9F)