[svn-r8038] Purpose:

Bug fix

Description:
    When two property lists are compared, the H5Pequal routine was just
comparing the raw information for the property values.  This causes problems
when the raw information contains pointers to other information.

Solution:
    Allow a 'compare' callback to be registered for properties, so that a user
application get perform the comparison itself, allowing for "deep" compares of
the property value.
    This was exported to the H5Pregister & H5Pinsert routines in the development
branch, but not the release branch.

Platforms tested:
    FreeBSD 4.9 (sleipnir)
    h5committest

doc/html/RM_H5P.html

@@ -4184,6 +4184,7 @@ SUBROUTINE
                   <em>H5P_prp_get_func_t</em> <code>get</code>,
                   <em>H5P_prp_delete_func_t</em> <code>delete</code>,
                   <em>H5P_prp_copy_func_t</em> <code>copy</code>,
+                  <em>H5P_prp_compare_func_t</em> <code>compare</code>,
                   <em>H5P_prp_close_func_t</em> <code>close</code>
 		)
 
@@ -4290,6 +4291,7 @@ SUBROUTINE
     routine returns an error value.
     </p>
 
+    <P>
     The <code>delete</code> routine is called when a property is being 
     deleted from a property list.  
     The <code>H5P_prp_delete_func_t</code> callback function is defined 
@@ -4323,6 +4325,7 @@ SUBROUTINE
     error value but the property is still deleted. 
     </P>
     
+    <P>
     The <code>copy</code> routine is called when a new property list 
     with this property is being created through a copy operation.  
     The <code>H5P_prp_copy_func_t</code> collback function is defined 
@@ -4349,6 +4352,36 @@ SUBROUTINE
     If the <code>copy</code> routine returns a negative value, the 
     new property value is not copied into the property and the 
     copy routine returns an error value.
+    </P>
+
+    <P>
+    The <code>compare</code> routine is called when a property list with 
+    this property is compared to another property list with the same property.
+    The <code>H5P_prp_compare_func_t</code> callback function is defined
+    as follows:
+        <ul><em>typedef int</em> (*<code>H5P_prp_compare_func_t</code>)(
+            <em>const void *</em><code>value1</code>,
+            <em>const void *</em><code>value2</code>,
+            <em>size_t </em><code>size</code>);
+        </ul>
+    The parameters to the callback function are defined as follows:
+    <ul><table>
+    <tr>
+        <td><em>const void *</em><code>value1</code></td>
+        <td>IN: The value of the first property to compare</td></tr>
+    <tr>
+        <td><em>const void *</em><code>value2</code></td>
+        <td>IN: The value of the second property to compare</td></tr>
+    <tr>
+        <td><em>size_t </em><code>size</code></td>
+        <td>IN: The size of the property in bytes</td></tr>
+    </table></ul>
+    The <code>compare</code> routine may <EM>not</EM> modify the values.
+    The <code>compare</code> routine should return a positive value if
+    <code>value1</code> is greater than <code>value2</code>, a negative value
+    if <code>value2</code> is greater than <code>value1</code> and zero if
+    <code>value1</code> and <code>value2</code> are equal.
+    </P>
 
     <P>The <code>close</code> routine is called when a property list 
     with this property is being closed.  
@@ -4722,6 +4755,7 @@ END SUBROUTINE h5pmodify_filter_f
                   <em>H5P_prp_get_func_t</em> <code>get</code>,
                   <em>H5P_prp_delete_func_t</em> <code>delete</code>,
                   <em>H5P_prp_copy_func_t</em> <code>copy</code>,
+                  <em>H5P_prp_compare_func_t</em> <code>compare</code>,
                   <em>H5P_prp_close_func_t</em> <code>close</code>
 				 )
 				 
@@ -4749,6 +4783,7 @@ END SUBROUTINE h5pmodify_filter_f
     <code>get</code> callbacks are never called.
     </P>
 	
+    <P>
     The <code>create</code> routine is called when a new property list 
     with this property is being created.  
     The <code>H5P_prp_create_func_t</code> callback function is defined 
@@ -4778,6 +4813,7 @@ END SUBROUTINE h5pmodify_filter_f
     create routine returns an error value.
     </P>
 	
+    <P>
     The <code>set</code> routine is called before a new value is copied 
     into the property.  
     The <code>H5P_prp_set_func_t</code> callback function is defined 
@@ -4855,6 +4891,7 @@ END SUBROUTINE h5pmodify_filter_f
     routine returns an error value.
     </P>
 
+    <P>
     The <code>delete</code> routine is called when a property is being 
     deleted from a property list.  
     The <code>H5P_prp_delete_func_t</code> callback function is defined 
@@ -4888,6 +4925,7 @@ END SUBROUTINE h5pmodify_filter_f
     an error value but the property is still deleted.
     </P>
 
+    <P>
     The <code>copy</code> routine is called when a new property list with 
     this property is being created through a copy operation.  
     The <code>H5P_prp_copy_func_t</code> callback function is defined
@@ -4916,6 +4954,36 @@ END SUBROUTINE h5pmodify_filter_f
     the copy routine returns an error value.
     </P>
 
+    <P>
+    The <code>compare</code> routine is called when a property list with 
+    this property is compared to another property list with the same property.
+    The <code>H5P_prp_compare_func_t</code> callback function is defined
+    as follows:
+        <ul><em>typedef int</em> (*<code>H5P_prp_compare_func_t</code>)(
+            <em>const void *</em><code>value1</code>,
+            <em>const void *</em><code>value2</code>,
+            <em>size_t </em><code>size</code>);
+        </ul>
+    The parameters to the callback function are defined as follows:
+    <ul><table>
+    <tr>
+        <td><em>const void *</em><code>value1</code></td>
+        <td>IN: The value of the first property to compare</td></tr>
+    <tr>
+        <td><em>const void *</em><code>value2</code></td>
+        <td>IN: The value of the second property to compare</td></tr>
+    <tr>
+        <td><em>size_t </em><code>size</code></td>
+        <td>IN: The size of the property in bytes</td></tr>
+    </table></ul>
+    The <code>compare</code> routine may <EM>not</EM> modify the values.
+    The <code>compare</code> routine should return a positive value if
+    <code>value1</code> is greater than <code>value2</code>, a negative value
+    if <code>value2</code> is greater than <code>value1</code> and zero if
+    <code>value1</code> and <code>value2</code> are equal.
+    </P>
+
+    <P>
     The <code>close</code> routine is called when a property list with 
     this property is being closed.  
     The <code>H5P_prp_close_func_t</code> callback function is defined 
@@ -4948,6 +5016,7 @@ END SUBROUTINE h5pmodify_filter_f
     If the <code>close</code> routine returns a negative value, 
     the property list close routine returns an error value but
     the property list is still closed.
+    </P>
 	
 <dt><strong>Parameters:</strong>
     <ul><dl>