libxml2で属性（xsi:nil="true"）を取得する

gistfile1.m

xmlNodePtr cur = ...;

/*****
 (1)
 */
xmlChar *prop = xmlGetProp(cur, (const xmlChar *) "nil");
// xmlChar *prop = xmlGetNsProp(cur, (const xmlChar *) "nil", (const xmlChar *) "http://www.w3.org/2001/XMLSchema-instance");

NSLog(@"prop : %p", prop);
if (prop != NULL) {
  NSString *value = [NSString stringWithCString:(char*)prop encoding:NSUTF8StringEncoding];
  NSLog(@"value >>>>>>>>>> %@", value);
  xmlFree(prop);
}

/*****
 (2) = (1)
 */
const xmlChar *ret=NULL;
xmlAttrPtr prop = cur->properties;

while( prop ) {
  if( xmlStrEqual( prop->name, (const xmlChar *) "xsi:nil" ) == 0 ) {
    ret = prop->name;
    break;
  }
  prop = prop->next;
}

if (ret != NULL) {
  NSString *value = [NSString stringWithCString:(char*)ret encoding:NSUTF8StringEncoding];
  NSLog(@"value >>>>>>>>>> %@", value);
  xmlFree(ret);
}