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

       DDI_MODEL_ILP32	   Current thread 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 5.11							    8 Feb 2001						    ddi_mmap_get_model(9F)