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

NAME

       ddi_prop_exists - check for the existence of a property

SYNOPSIS

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

       int ddi_prop_exists(dev_t match_dev, dev_info_t *dip, uint_t flags, char *name);

INTERFACE LEVEL

       Solaris DDI specific (Solaris DDI).

PARAMETERS

       match_dev       Device number associated with property or DDI_DEV_T_ANY.

       dip	       Pointer to the device info node of device whose property list should be searched.

       flags	       Possible flag values are some combination of:

		       "small and bold">DDI_PROP_DONTPASS

			   Do not pass request to parent device information node if the property  is not found.

		       DDI_PROP_NOTPROM

			   Do not look at  PROM properties (ignored on platforms that do not support
			    PROM properties).

       name	       String containing the name of the property.

DESCRIPTION

       ddi_prop_exists() checks for the existence of a property regardless  of the property value data type.

       Properties are searched for based on the dip, name, and	match_dev. The property search order is as follows:

       1.  Search software properties created by the driver.

       2.  Search the software properties created by the system (or nexus nodes in the device info tree).

       3.  Search the driver global properties list.

       4.  If DDI_PROP_NOTPROM is not set, search the PROM properties (if they exist).

       5.  If DDI_PROP_DONTPASS is not set, pass this request to the parent device information node.

       6.  Return 0 if not found and 1 if found.

       Usually,  the  match_dev  argument  should  be  set  to	the  actual  device number that this property is associated with.  However, if the
       match_dev argument is DDI_DEV_T_ANY, then  ddi_prop_exists() will match the request  regardless of the  match_dev the property was  created
       with.   That  is  the  first  property  whose  name  matches  name  will  be  returned.	 If  a property was created with  match_dev set to
       DDI_DEV_T_NONE then the only way to look up this property is with a  match_dev set to DDI_DEV_T_ANY. PROM  properties  are  always  created
       with match_dev set to DDI_DEV_T_NONE.

       name must always be set to the name of the property being looked up.

RETURN VALUES

       ddi_prop_exists() returns  1 if the property exists and	0 otherwise.

CONTEXT

       These functions can be called from user or kernel context.

EXAMPLES

       Example 1: : Using ddi_prop_exists()

       The following example demonstrates the use of  ddi_prop_exists().

       /*
	    * Enable "whizzy" mode if the "whizzy-mode" property exists
	    */
	    if (ddi_prop_exists(xx_dev, xx_dip, DDI_PROP_NOTPROM,
		    "whizzy-mode") == 1) {
		  xx_enable_whizzy_mode(xx_dip);
	    } else {
		  xx_disable_whizzy_mode(xx_dip);
	    }

SEE ALSO

       ddi_prop_get_int(9F), ddi_prop_lookup(9F), ddi_prop_remove(9F), ddi_prop_update(9F)

       Writing Device Drivers

SunOS 5.10							    22 May 1995 					       ddi_prop_exists(9F)