diff --git a/giobjectinfo.c b/giobjectinfo.c
index 6f9e04612..dc26709ed 100644
--- a/giobjectinfo.c
+++ b/giobjectinfo.c
@@ -25,12 +25,46 @@
 #include "girepository-private.h"
 #include "gitypelib-internal.h"
 
-/* GIObjectInfo functions */
+/**
+ * SECTION:giobjectinfo
+ * @Short_description: Struct representing a GObject
+ * @Title: GIObjectInfo
+ *
+ * GIPropertyInfo represents a #GObject. This doesn't represent a specific
+ * instance of a GObject, instead this represent the object type (eg class).
+ *
+ * A GObject has methods, fields, properties, signals, interfaces, constants
+ * and virtual functions.
+ *
+ * <refsect1 id="gi-giobjectinfo.struct-hierarchy" role="struct_hierarchy">
+ * <title role="struct_hierarchy.title">Struct hierarchy</title>
+ * <synopsis>
+ *   <link linkend="gi-GIBaseInfo">GIBaseInfo</link>
+ *    +----<link linkend="gi-GIRegisteredTypeInfo">GIRegisteredTypeInfo</link>
+ *          +----GIObjectInfo
+ * </synopsis>
+ * </refsect1>
+ */
+
+/**
+ * g_object_info_get_parent:
+ * @info: a #GIObjectInfo
+ *
+ * Obtain the parent of the object type.
+ *
+ * Returns: (transfer full): the #GIObjectInfo. Free the struct by calling
+ * g_base_info_unref() when done.
+ */
 GIObjectInfo *
 g_object_info_get_parent (GIObjectInfo *info)
 {
   GIRealInfo *rinfo = (GIRealInfo *)info;
-  ObjectBlob *blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
+  ObjectBlob *blob;
+
+  g_return_val_if_fail (info != NULL, NULL);
+  g_return_val_if_fail (GI_IS_OBJECT_INFO (info), NULL);
+
+  blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
 
   if (blob->parent)
     return (GIObjectInfo *) _g_info_from_entry (rinfo->repository,
@@ -39,69 +73,168 @@ g_object_info_get_parent (GIObjectInfo *info)
     return NULL;
 }
 
+/**
+ * g_object_info_get_abstract:
+ * @info: a #GIObjectInfo
+ *
+ * Obtain if the object type is an abstract type, eg if it cannot be
+ * instantiated
+ *
+ * Returns: %TRUE if the object type is abstract
+ */
 gboolean
-g_object_info_get_abstract (GIObjectInfo    *info)
+g_object_info_get_abstract (GIObjectInfo *info)
 {
   GIRealInfo *rinfo = (GIRealInfo *)info;
-  ObjectBlob *blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
+  ObjectBlob *blob;
+
+  g_return_val_if_fail (info != NULL, FALSE);
+  g_return_val_if_fail (GI_IS_OBJECT_INFO (info), FALSE);
+
+  blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
+
   return blob->abstract != 0;
 }
 
+/**
+ * g_object_info_get_type_name:
+ * @info: a #GIObjectInfo
+ *
+ * Obtain the name of the objects class/type.
+ *
+ * Returns: name of the objects type
+ */
 const gchar *
 g_object_info_get_type_name (GIObjectInfo *info)
 {
   GIRealInfo *rinfo = (GIRealInfo *)info;
-  ObjectBlob *blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
+  ObjectBlob *blob;
+
+  g_return_val_if_fail (info != NULL, NULL);
+  g_return_val_if_fail (GI_IS_OBJECT_INFO (info), NULL);
+
+  blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
 
   return g_typelib_get_string (rinfo->typelib, blob->gtype_name);
 }
 
+/**
+ * g_object_info_get_type_init:
+ * @info: a #GIObjectInfo
+ *
+ * Obtain the function which when called will return the GType
+ * function for which this object type is registered.
+ *
+ * Returns: the type init function
+ */
 const gchar *
 g_object_info_get_type_init (GIObjectInfo *info)
 {
   GIRealInfo *rinfo = (GIRealInfo *)info;
-  ObjectBlob *blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
+  ObjectBlob *blob;
+
+  g_return_val_if_fail (info != NULL, NULL);
+  g_return_val_if_fail (GI_IS_OBJECT_INFO (info), NULL);
+
+  blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
 
   return g_typelib_get_string (rinfo->typelib, blob->gtype_init);
 }
 
+/**
+ * g_object_info_get_n_interfaces:
+ * @info: a #GIObjectInfo
+ *
+ * Obtain the number of interfaces that this object type has.
+ *
+ * Returns: number of interfaces
+ */
 gint
 g_object_info_get_n_interfaces (GIObjectInfo *info)
 {
   GIRealInfo *rinfo = (GIRealInfo *)info;
-  ObjectBlob *blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
+  ObjectBlob *blob;
+
+  g_return_val_if_fail (info != NULL, 0);
+  g_return_val_if_fail (GI_IS_OBJECT_INFO (info), 0);
+
+  blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
 
   return blob->n_interfaces;
 }
 
+/**
+ * g_object_info_get_interface:
+ * @info: a #GIObjectInfo
+ * @n: index of interface to get
+ *
+ * Obtain an object type interface at index @n.
+ *
+ * Returns: (transfer full): the #GIInterfaceInfo. Free the struct by calling
+ * g_base_info_unref() when done.
+ */
 GIInterfaceInfo *
 g_object_info_get_interface (GIObjectInfo *info,
 			     gint          n)
 {
   GIRealInfo *rinfo = (GIRealInfo *)info;
-  ObjectBlob *blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
+  ObjectBlob *blob;
+
+  g_return_val_if_fail (info != NULL, NULL);
+  g_return_val_if_fail (GI_IS_OBJECT_INFO (info), NULL);
+
+  blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
 
   return (GIInterfaceInfo *) _g_info_from_entry (rinfo->repository,
 						 rinfo->typelib, blob->interfaces[n]);
 }
 
+/**
+ * g_object_info_get_n_fields:
+ * @info: a #GIObjectInfo
+ *
+ * Obtain the number of fields that this object type has.
+ *
+ * Returns: number of fields
+ */
 gint
 g_object_info_get_n_fields (GIObjectInfo *info)
 {
   GIRealInfo *rinfo = (GIRealInfo *)info;
-  ObjectBlob *blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
+  ObjectBlob *blob;
+
+  g_return_val_if_fail (info != NULL, 0);
+  g_return_val_if_fail (GI_IS_OBJECT_INFO (info), 0);
+
+  blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
 
   return blob->n_fields;
 }
 
+/**
+ * g_object_info_get_field:
+ * @info: a #GIObjectInfo
+ * @n: index of field to get
+ *
+ * Obtain an object type field at index @n.
+ *
+ * Returns: (transfer full): the #GIFieldInfo. Free the struct by calling
+ * g_base_info_unref() when done.
+ */
 GIFieldInfo *
 g_object_info_get_field (GIObjectInfo *info,
 			 gint          n)
 {
   gint offset;
   GIRealInfo *rinfo = (GIRealInfo *)info;
-  Header *header = (Header *)rinfo->typelib->data;
-  ObjectBlob *blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
+  Header *header;
+  ObjectBlob *blob;
+
+  g_return_val_if_fail (info != NULL, NULL);
+  g_return_val_if_fail (GI_IS_OBJECT_INFO (info), NULL);
+
+  header = (Header *)rinfo->typelib->data;
+  blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
 
   offset = rinfo->offset + header->object_blob_size
     + (blob->n_interfaces + blob->n_interfaces % 2) * 2
@@ -110,23 +243,51 @@ g_object_info_get_field (GIObjectInfo *info,
   return (GIFieldInfo *) g_info_new (GI_INFO_TYPE_FIELD, (GIBaseInfo*)info, rinfo->typelib, offset);
 }
 
+/**
+ * g_object_info_get_n_properties:
+ * @info: a #GIObjectInfo
+ *
+ * Obtain the number of properties that this object type has.
+ *
+ * Returns: number of properties
+ */
 gint
 g_object_info_get_n_properties (GIObjectInfo *info)
 {
   GIRealInfo *rinfo = (GIRealInfo *)info;
-  ObjectBlob *blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
+  ObjectBlob *blob;
 
+  g_return_val_if_fail (info != NULL, 0);
+  g_return_val_if_fail (GI_IS_OBJECT_INFO (info), 0);
+
+  blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
   return blob->n_properties;
 }
 
+/**
+ * g_object_info_get_property:
+ * @info: a #GIObjectInfo
+ * @n: index of property to get
+ *
+ * Obtain an object type property at index @n.
+ *
+ * Returns: (transfer full): the #GIPropertyInfo. Free the struct by calling
+ * g_base_info_unref() when done.
+ */
 GIPropertyInfo *
 g_object_info_get_property (GIObjectInfo *info,
 			    gint          n)
 {
   gint offset;
   GIRealInfo *rinfo = (GIRealInfo *)info;
-  Header *header = (Header *)rinfo->typelib->data;
-  ObjectBlob *blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
+  Header *header;
+  ObjectBlob *blob;
+
+  g_return_val_if_fail (info != NULL, NULL);
+  g_return_val_if_fail (GI_IS_OBJECT_INFO (info), NULL);
+
+  header = (Header *)rinfo->typelib->data;
+  blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
 
   offset = rinfo->offset + header->object_blob_size
     + (blob->n_interfaces + blob->n_interfaces % 2) * 2
@@ -137,23 +298,53 @@ g_object_info_get_property (GIObjectInfo *info,
 					rinfo->typelib, offset);
 }
 
+/**
+ * g_object_info_get_n_methods:
+ * @info: a #GIObjectInfo
+ *
+ * Obtain the number of methods that this object type has.
+ *
+ * Returns: number of methods
+ */
 gint
 g_object_info_get_n_methods (GIObjectInfo *info)
 {
   GIRealInfo *rinfo = (GIRealInfo *)info;
-  ObjectBlob *blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
+  ObjectBlob *blob;
+
+  g_return_val_if_fail (info != NULL, 0);
+  g_return_val_if_fail (GI_IS_OBJECT_INFO (info), 0);
+
+  blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
 
   return blob->n_methods;
 }
 
+/**
+ * g_object_info_get_method:
+ * @info: a #GIObjectInfo
+ * @n: index of method to get
+ *
+ * Obtain an object type method at index @n.
+ *
+ * Returns: (transfer full): the #GIFunctionInfo. Free the struct by calling
+ * g_base_info_unref() when done.
+ */
 GIFunctionInfo *
 g_object_info_get_method (GIObjectInfo *info,
 			  gint          n)
 {
   gint offset;
   GIRealInfo *rinfo = (GIRealInfo *)info;
-  Header *header = (Header *)rinfo->typelib->data;
-  ObjectBlob *blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
+  Header *header;
+  ObjectBlob *blob;
+
+  g_return_val_if_fail (info != NULL, NULL);
+  g_return_val_if_fail (GI_IS_OBJECT_INFO (info), NULL);
+
+  header = (Header *)rinfo->typelib->data;
+  blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
+
 
   offset = rinfo->offset + header->object_blob_size
     + (blob->n_interfaces + blob->n_interfaces % 2) * 2
@@ -165,14 +356,27 @@ g_object_info_get_method (GIObjectInfo *info,
 					  rinfo->typelib, offset);
 }
 
+/**
+ * g_object_info_find_method:
+ * @info: a #GIObjectInfo
+ *
+ * Returns: (transfer full): the #GIFunctionInfo. Free the struct by calling
+ * g_base_info_unref() when done.
+ */
 GIFunctionInfo *
 g_object_info_find_method (GIObjectInfo *info,
 			   const gchar  *name)
 {
   gint offset;
   GIRealInfo *rinfo = (GIRealInfo *)info;
-  Header *header = (Header *)rinfo->typelib->data;
-  ObjectBlob *blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
+  Header *header;
+  ObjectBlob *blob;
+
+  g_return_val_if_fail (info != NULL, 0);
+  g_return_val_if_fail (GI_IS_OBJECT_INFO (info), 0);
+
+  header = (Header *)rinfo->typelib->data;
+  blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
 
   offset = rinfo->offset + header->object_blob_size
     + (blob->n_interfaces + blob->n_interfaces % 2) * 2
@@ -182,23 +386,52 @@ g_object_info_find_method (GIObjectInfo *info,
   return _g_base_info_find_method ((GIBaseInfo*)info, offset, blob->n_methods, name);
 }
 
+/**
+ * g_object_info_get_n_signals:
+ * @info: a #GIObjectInfo
+ *
+ * Obtain the number of signals that this object type has.
+ *
+ * Returns: number of signals
+ */
 gint
 g_object_info_get_n_signals (GIObjectInfo *info)
 {
   GIRealInfo *rinfo = (GIRealInfo *)info;
-  ObjectBlob *blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
+  ObjectBlob *blob;
+
+  g_return_val_if_fail (info != NULL, 0);
+  g_return_val_if_fail (GI_IS_OBJECT_INFO (info), 0);
+
+  blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
 
   return blob->n_signals;
 }
 
+/**
+ * g_object_info_get_signal:
+ * @info: a #GIObjectInfo
+ * @n: index of signal to get
+ *
+ * Obtain an object type signal at index @n.
+ *
+ * Returns: (transfer full): the #GISignalInfo. Free the struct by calling
+ * g_base_info_unref() when done.
+ */
 GISignalInfo *
 g_object_info_get_signal (GIObjectInfo *info,
 			  gint          n)
 {
   gint offset;
   GIRealInfo *rinfo = (GIRealInfo *)info;
-  Header *header = (Header *)rinfo->typelib->data;
-  ObjectBlob *blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
+  Header *header;
+  ObjectBlob *blob;
+
+  g_return_val_if_fail (info != NULL, NULL);
+  g_return_val_if_fail (GI_IS_OBJECT_INFO (info), NULL);
+
+  header = (Header *)rinfo->typelib->data;
+  blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
 
   offset = rinfo->offset + header->object_blob_size
     + (blob->n_interfaces + blob->n_interfaces % 2) * 2
@@ -211,23 +444,52 @@ g_object_info_get_signal (GIObjectInfo *info,
 				      rinfo->typelib, offset);
 }
 
+/**
+ * g_object_info_get_n_vfuncs:
+ * @info: a #GIObjectInfo
+ *
+ * Obtain the number of virtual functions that this object type has.
+ *
+ * Returns: number of virtual functions
+ */
 gint
 g_object_info_get_n_vfuncs (GIObjectInfo *info)
 {
   GIRealInfo *rinfo = (GIRealInfo *)info;
-  ObjectBlob *blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
+  ObjectBlob *blob;
+
+  g_return_val_if_fail (info != NULL, 0);
+  g_return_val_if_fail (GI_IS_OBJECT_INFO (info), 0);
+
+  blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
 
   return blob->n_vfuncs;
 }
 
+/**
+ * g_object_info_get_vfunc:
+ * @info: a #GIObjectInfo
+ * @n: index of virtual function to get
+ *
+ * Obtain an object type virtual function at index @n.
+ *
+ * Returns: (transfer full): the #GIVFuncInfo. Free the struct by calling
+ * g_base_info_unref() when done.
+ */
 GIVFuncInfo *
 g_object_info_get_vfunc (GIObjectInfo *info,
 			 gint          n)
 {
   gint offset;
   GIRealInfo *rinfo = (GIRealInfo *)info;
-  Header *header = (Header *)rinfo->typelib->data;
-  ObjectBlob *blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
+  Header *header;
+  ObjectBlob *blob;
+
+  g_return_val_if_fail (info != NULL, NULL);
+  g_return_val_if_fail (GI_IS_OBJECT_INFO (info), NULL);
+
+  header = (Header *)rinfo->typelib->data;
+  blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
 
   offset = rinfo->offset + header->object_blob_size
     + (blob->n_interfaces + blob->n_interfaces % 2) * 2
@@ -263,8 +525,14 @@ g_object_info_find_vfunc (GIObjectInfo *info,
 {
   gint offset;
   GIRealInfo *rinfo = (GIRealInfo *)info;
-  Header *header = (Header *)rinfo->typelib->data;
-  ObjectBlob *blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
+  Header *header;
+  ObjectBlob *blob;
+
+  g_return_val_if_fail (info != NULL, NULL);
+  g_return_val_if_fail (GI_IS_OBJECT_INFO (info), NULL);
+
+  header = (Header *)rinfo->typelib->data;
+  blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
 
   offset = rinfo->offset + header->object_blob_size
     + (blob->n_interfaces + blob->n_interfaces % 2) * 2
@@ -276,23 +544,52 @@ g_object_info_find_vfunc (GIObjectInfo *info,
   return _g_base_info_find_vfunc (rinfo, offset, blob->n_vfuncs, name);
 }
 
+/**
+ * g_object_info_get_n_constants:
+ * @info: a #GIObjectInfo
+ *
+ * Obtain the number of constants that this object type has.
+ *
+ * Returns: number of constants
+ */
 gint
 g_object_info_get_n_constants (GIObjectInfo *info)
 {
   GIRealInfo *rinfo = (GIRealInfo *)info;
-  ObjectBlob *blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
+  ObjectBlob *blob;
+
+  g_return_val_if_fail (info != NULL, 0);
+  g_return_val_if_fail (GI_IS_OBJECT_INFO (info), 0);
+
+  blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
 
   return blob->n_constants;
 }
 
+/**
+ * g_object_info_get_constant:
+ * @info: a #GIObjectInfo
+ * @n: index of constant to get
+ *
+ * Obtain an object type constant at index @n.
+ *
+ * Returns: (transfer full): the #GIConstantInfo. Free the struct by calling
+ * g_base_info_unref() when done.
+ */
 GIConstantInfo *
 g_object_info_get_constant (GIObjectInfo *info,
 			    gint          n)
 {
   gint offset;
   GIRealInfo *rinfo = (GIRealInfo *)info;
-  Header *header = (Header *)rinfo->typelib->data;
-  ObjectBlob *blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
+  Header *header;
+  ObjectBlob *blob;
+
+  g_return_val_if_fail (info != NULL, NULL);
+  g_return_val_if_fail (GI_IS_OBJECT_INFO (info), NULL);
+
+  header = (Header *)rinfo->typelib->data;
+  blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
 
   offset = rinfo->offset + header->object_blob_size
     + (blob->n_interfaces + blob->n_interfaces % 2) * 2
@@ -321,7 +618,12 @@ GIStructInfo *
 g_object_info_get_class_struct (GIObjectInfo *info)
 {
   GIRealInfo *rinfo = (GIRealInfo *)info;
-  ObjectBlob *blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
+  ObjectBlob *blob;
+
+  g_return_val_if_fail (info != NULL, NULL);
+  g_return_val_if_fail (GI_IS_OBJECT_INFO (info), NULL);
+
+  blob = (ObjectBlob *)&rinfo->typelib->data[rinfo->offset];
 
   if (blob->gtype_struct)
     return (GIStructInfo *) _g_info_from_entry (rinfo->repository,