'\" te
.\" Copyright (c) 1995, Sun Microsystems, Inc.
.TH ddi_prop_exists 9F "22 May 1995" "SunOS 5.11" "Kernel Functions for Drivers"
.SH NAME
ddi_prop_exists \- check for the existence of a property
.SH SYNOPSIS
.LP
.nf
#include <sys/ddi.h>
#include <sys/sunddi.h>

\fBint\fR \fBddi_prop_exists\fR(\fBdev_t\fR \fImatch_dev\fR, \fBdev_info_t *\fR\fIdip\fR, \fBuint_t\fR \fIflags\fR, 
     \fBchar *\fR\fIname\fR);
.fi

.SH INTERFACE LEVEL
.sp
.LP
Solaris DDI specific (Solaris DDI).
.SH PARAMETERS
.sp
.ne 2
.mk
.na
\fB\fImatch_dev\fR \fR
.ad
.RS 14n
.rt  
Device number associated with property or \fBDDI_DEV_T_ANY.\fR 
.RE

.sp
.ne 2
.mk
.na
\fB\fIdip\fR \fR
.ad
.RS 14n
.rt  
Pointer to the device info node of device whose property list should be searched.
.RE

.sp
.ne 2
.mk
.na
\fB\fIflags\fR \fR
.ad
.RS 14n
.rt  
Possible flag values are some combination of: 
.sp
.ne 2
.mk
.na
\fB\fBDDI_PROP_DONTPASS\fR \fR
.ad
.RS 22n
.rt  
Do not pass request to parent device information node if the property  is not found.
.RE

.sp
.ne 2
.mk
.na
\fB\fBDDI_PROP_NOTPROM\fR \fR
.ad
.RS 22n
.rt  
Do not look at  \fBPROM \fRproperties (ignored on platforms that do not support  \fBPROM \fRproperties).
.RE

.RE

.sp
.ne 2
.mk
.na
\fB\fIname\fR \fR
.ad
.RS 14n
.rt  
String containing the name of the property.
.RE

.SH DESCRIPTION
.sp
.LP
\fBddi_prop_exists()\fR checks for the existence of a property regardless  of the property value data type.
.sp
.LP
Properties are searched for based on the \fIdip\fR, \fIname\fR, and  \fImatch_dev\fR. The property search order is as follows:
.RS +4
.TP
1.
Search software properties created by the driver.
.RE
.RS +4
.TP
2.
Search the software properties created by the system (or nexus nodes in the device info tree).
.RE
.RS +4
.TP
3.
Search the driver global properties list.
.RE
.RS +4
.TP
4.
If \fBDDI_PROP_NOTPROM\fR is not set, search the \fBPROM \fRproperties (if they exist).
.RE
.RS +4
.TP
5.
If \fBDDI_PROP_DONTPASS\fR is not set, pass this request to the parent device information node.
.RE
.RS +4
.TP
6.
Return \fB0\fR if not found and \fB1\fR if found.
.RE
.sp
.LP
Usually, the \fImatch_dev\fR argument should be set to the actual device number that this property is associated with.  However, if the  \fImatch_dev\fR argument is \fBDDI_DEV_T_ANY,\fR then  \fBddi_prop_exists()\fR will match the request  regardless of the  \fImatch_dev\fR the property was created with.  That is the first property whose name matches \fIname\fR will be returned.  If a property was created with  \fImatch_dev\fR set to  \fBDDI_DEV_T_NONE\fR then the only way to look up this property is with a  \fImatch_dev\fR set to \fBDDI_DEV_T_ANY.\fR \fBPROM \fRproperties are always created with \fImatch_dev\fR set to \fBDDI_DEV_T_NONE.\fR 
.sp
.LP
\fIname\fR must always be set to the name of the property being looked up.
.SH RETURN VALUES
.sp
.LP
\fBddi_prop_exists()\fR returns  \fB1\fR if the property exists and  \fB0\fR otherwise.
.SH CONTEXT
.sp
.LP
These functions can be called from user or kernel context.
.SH EXAMPLES
.LP
\fBExample 1 \fR: Using \fBddi_prop_exists()\fR 
.sp
.LP
The following example demonstrates the use of  \fBddi_prop_exists()\fR.

.sp
.in +2
.nf
/*
	* 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);
	}
.fi
.in -2

.SH SEE ALSO
.sp
.LP
\fBddi_prop_get_int\fR(9F), \fBddi_prop_lookup\fR(9F), \fBddi_prop_remove\fR(9F), \fBddi_prop_update\fR(9F) 
.sp
.LP
\fIWriting Device Drivers for Oracle Solaris 11.2\fR