path: root/src/H5A.c

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by The HDF Group.                                               *
 * Copyright by the Board of Trustees of the University of Illinois.         *
 * All rights reserved.                                                      *
 *                                                                           *
 * This file is part of HDF5.  The full HDF5 copyright notice, including     *
 * terms governing use, modification, and redistribution, is contained in    *
 * the COPYING file, which can be found at the root of the source code       *
 * distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases.  *
 * If you do not have access to either file, you may request a copy from     *
 * help@hdfgroup.org.                                                        *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/****************/
/* Module Setup */
/****************/

#include "H5Amodule.h"          /* This source code file is part of the H5A module */
#define H5O_FRIEND              /* Suppress error about including H5Opkg */


/***********/
/* Headers */
/***********/
#include "H5private.h"          /* Generic Functions                        */
#include "H5Apkg.h"             /* Attributes                               */
#include "H5CXprivate.h"        /* API Contexts                             */
#include "H5Eprivate.h"         /* Error handling                           */
#include "H5FLprivate.h"        /* Free Lists                               */
#include "H5Iprivate.h"         /* IDs                                      */
#include "H5MMprivate.h"        /* Memory management                        */
#include "H5Opkg.h"             /* Object headers                           */
#include "H5Sprivate.h"         /* Dataspace functions                      */
#include "H5VLprivate.h"        /* Virtual Object Layer                     */


/****************/
/* Local Macros */
/****************/


/******************/
/* Local Typedefs */
/******************/

/* Object header iterator callbacks */
/* Data structure for callback for locating the index by name */
typedef struct H5A_iter_cb1 {
    const char *name;
    int idx;
} H5A_iter_cb1;


/********************/
/* Package Typedefs */
/********************/


/********************/
/* Local Prototypes */
/********************/


/*********************/
/* Package Variables */
/*********************/

/* Package initialization variable */
hbool_t H5_PKG_INIT_VAR = FALSE;


/*****************************/
/* Library Private Variables */
/*****************************/


/*******************/
/* Local Variables */
/*******************/

/* Declare the free lists of H5A_t */
H5FL_DEFINE(H5A_t);

/* Declare the free lists for H5A_shared_t's */
H5FL_DEFINE(H5A_shared_t);

/* Declare a free list to manage blocks of type conversion data */
H5FL_BLK_DEFINE(attr_buf);

/* Attribute ID class */
static const H5I_class_t H5I_ATTR_CLS[1] = {{
    H5I_ATTR,                   /* ID class value */
    0,                          /* Class flags */
    0,                          /* # of reserved IDs for class */
    (H5I_free_t)H5A__close_cb   /* Callback routine for closing objects of this class */
}};

/* Flag indicating "top" of interface has been initialized */
static hbool_t H5A_top_package_initialize_s = FALSE;



/*--------------------------------------------------------------------------
NAME
   H5A__init_package -- Initialize interface-specific information
USAGE
    herr_t H5A__init_package()

RETURNS
    Non-negative on success/Negative on failure
DESCRIPTION
    Initializes any interface-specific data or routines.

--------------------------------------------------------------------------*/
herr_t
H5A__init_package(void)
{
    herr_t ret_value = SUCCEED;   /* Return value */

    FUNC_ENTER_PACKAGE

    /*
     * Create attribute ID type.
     */
    if(H5I_register_type(H5I_ATTR_CLS) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, FAIL, "unable to initialize interface")

    /* Mark "top" of interface as initialized, too */
    H5A_top_package_initialize_s = TRUE;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A__init_package() */


/*--------------------------------------------------------------------------
 NAME
    H5A_top_term_package
 PURPOSE
    Terminate various H5A objects
 USAGE
    void H5A_top_term_package()
 RETURNS
 DESCRIPTION
    Release IDs for the atom group, deferring full interface shutdown
    until later (in H5A_term_package).
 GLOBAL VARIABLES
 COMMENTS, BUGS, ASSUMPTIONS
     Can't report errors...
 EXAMPLES
 REVISION LOG
--------------------------------------------------------------------------*/
int
H5A_top_term_package(void)
{
    int	n = 0;

    FUNC_ENTER_NOAPI_NOINIT_NOERR

    if(H5A_top_package_initialize_s) {
	if(H5I_nmembers(H5I_ATTR) > 0) {
	    (void)H5I_clear_type(H5I_ATTR, FALSE, FALSE);
            n++; /*H5I*/
	} /* end if */

        /* Mark closed */
        if(0 == n)
            H5A_top_package_initialize_s = FALSE;
    } /* end if */

    FUNC_LEAVE_NOAPI(n)
} /* H5A_top_term_package() */


/*--------------------------------------------------------------------------
 NAME
    H5A_term_package
 PURPOSE
    Terminate various H5A objects
 USAGE
    void H5A_term_package()
 RETURNS
 DESCRIPTION
    Release any other resources allocated.
 GLOBAL VARIABLES
 COMMENTS, BUGS, ASSUMPTIONS
     Can't report errors...

     Finishes shutting down the interface, after H5A_top_term_package()
     is called
 EXAMPLES
 REVISION LOG
--------------------------------------------------------------------------*/
int
H5A_term_package(void)
{
    int	n = 0;

    FUNC_ENTER_NOAPI_NOINIT_NOERR

    if(H5_PKG_INIT_VAR) {
        /* Sanity checks */
        HDassert(0 == H5I_nmembers(H5I_ATTR));
        HDassert(FALSE == H5A_top_package_initialize_s);

        /* Destroy the attribute object id group */
        n += (H5I_dec_type_ref(H5I_ATTR) > 0);

        /* Mark closed */
        if(0 == n)
            H5_PKG_INIT_VAR = FALSE;
    } /* end if */

    FUNC_LEAVE_NOAPI(n)
} /* H5A_term_package() */


/*--------------------------------------------------------------------------
 * Function:    H5Acreate2
 *
 * Purpose:     Creates an attribute on an object
 *
 * Usage:
 *              hid_t H5Acreate2(loc_id, attr_name, type_id, space_id, acpl_id,
 *                  aapl_id)
 *
 * Description: This function creates an attribute which is attached to the
 *              object specified with 'loc_id'. The name specified with
 *              'attr_name' for each attribute for an object must be unique
 *              for that object. The 'type_id' and 'space_id' are created
 *              with the H5T and H5S interfaces respectively. The 'aapl_id'
 *              property list is currently unused, but will be used in the
 *              future for optional attribute access properties. The
 *              attribute ID returned from this function must be released
 *              with H5Aclose or resource leaks will develop.
 *
 * Parameters:
 *              hid_t loc_id;           IN: Object (dataset or group) to be attached to
 *              const char *attr_name;  IN: Name of attribute to locate and open
 *              hid_t type_id;          IN: ID of datatype for attribute
 *              hid_t space_id;         IN: ID of dataspace for attribute
 *              hid_t acpl_id;          IN: ID of creation property list (currently not used)
 *              hid_t aapl_id;          IN: Attribute access property list
 *
 * Return:      Success:    An ID for the created attribute
 *
 *              Failure:    H5I_INVALID_HID
 *
 *-------------------------------------------------------------------------
 */
hid_t
H5Acreate2(hid_t loc_id, const char *attr_name, hid_t type_id, hid_t space_id,
    hid_t acpl_id, hid_t aapl_id)
{
    void           *attr = NULL;                        /* Attribute created            */
    H5VL_object_t  *vol_obj = NULL;                         /* Object token of loc_id       */
    H5VL_loc_params_t   loc_params;
    hid_t           ret_value = H5I_INVALID_HID;        /* Return value                 */

    FUNC_ENTER_API(H5I_INVALID_HID)
    H5TRACE6("i", "i*siiii", loc_id, attr_name, type_id, space_id, acpl_id, aapl_id);

    /* Check arguments */
    if(H5I_ATTR == H5I_get_type(loc_id))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "location is not valid for an attribute")
    if(!attr_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "attr_name parameter cannot be NULL")
    if(!*attr_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "attr_name parameter cannot be an empty string")

    /* Get correct property list */
    if(H5P_DEFAULT == acpl_id)
        acpl_id = H5P_ATTRIBUTE_CREATE_DEFAULT;

    /* Verify access property list and set up collective metadata if appropriate */
    if(H5CX_set_apl(&aapl_id, H5P_CLS_AACC, loc_id, TRUE) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTSET, H5I_INVALID_HID, "can't set access property list info")

    /* Get the location object */
    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid location identifier")

    /* Set location parameters */
    loc_params.type     = H5VL_OBJECT_BY_SELF;
    loc_params.obj_type = H5I_get_type(loc_id);

    /* Create the attribute */
    if(NULL == (attr = H5VL_attr_create(vol_obj, &loc_params, attr_name, type_id, space_id, acpl_id, aapl_id, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL)))
        HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, H5I_INVALID_HID, "unable to create attribute")

    /* Register the new attribute and get an ID for it */
    if((ret_value = H5VL_register(H5I_ATTR, attr, vol_obj->connector, TRUE)) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTREGISTER, H5I_INVALID_HID, "unable to atomize attribute handle")

done:
    /* Cleanup on failure */
    if(H5I_INVALID_HID == ret_value)
        if(attr && H5VL_attr_close(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) < 0)
            HDONE_ERROR(H5E_ATTR, H5E_CLOSEERROR, H5I_INVALID_HID, "can't close attribute")

    FUNC_LEAVE_API(ret_value)
} /* H5Acreate2() */


/*--------------------------------------------------------------------------
 NAME
    H5Acreate_by_name
 PURPOSE
    Creates an attribute on an object
 USAGE
    hid_t H5Acreate_by_name(loc_id, obj_name, attr_name, type_id, space_id, acpl_id,
            aapl_id, lapl_id)
        hid_t loc_id;       IN: Object (dataset or group) to be attached to
        const char *obj_name;   IN: Name of object relative to location
        const char *attr_name;  IN: Name of attribute to locate and open
        hid_t type_id;          IN: ID of datatype for attribute
        hid_t space_id;         IN: ID of dataspace for attribute
        hid_t acpl_id;          IN: ID of creation property list (currently not used)
        hid_t aapl_id;          IN: Attribute access property list
        hid_t lapl_id;          IN: Link access property list
 RETURNS
    Non-negative on success/H5I_INVALID_HID on failure

 DESCRIPTION
        This function creates an attribute which is attached to the object
    specified with 'loc_id/obj_name'.  The name specified with 'attr_name' for
    each attribute for an object must be unique for that object.  The 'type_id'
    and 'space_id' are created with the H5T and H5S interfaces respectively.
    The 'aapl_id' property list is currently unused, but will be used in the
    future for optional attribute access properties.  The attribute ID returned
    from this function must be released with H5Aclose or resource leaks will
    develop.

--------------------------------------------------------------------------*/
hid_t
H5Acreate_by_name(hid_t loc_id, const char *obj_name, const char *attr_name,
    hid_t type_id, hid_t space_id, hid_t acpl_id, hid_t aapl_id,
    hid_t lapl_id)
{
    void               *attr = NULL;                /* attr token from VOL connector */
    H5VL_object_t      *vol_obj = NULL;        /* object token of loc_id */
    H5VL_loc_params_t   loc_params;
    hid_t               ret_value = H5I_INVALID_HID;    /* Return value */

    FUNC_ENTER_API(H5I_INVALID_HID)
    H5TRACE8("i", "i*s*siiiii", loc_id, obj_name, attr_name, type_id, space_id,
             acpl_id, aapl_id, lapl_id);

    /* Check arguments */
    if(H5I_ATTR == H5I_get_type(loc_id))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "location is not valid for an attribute")
    if(!obj_name || !*obj_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "no object name")
    if(!attr_name || !*attr_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "no attribute name")

    /* Get correct property list */
    if(H5P_DEFAULT == acpl_id)
        acpl_id = H5P_ATTRIBUTE_CREATE_DEFAULT;

    /* Verify access property list and set up collective metadata if appropriate */
    if(H5CX_set_apl(&aapl_id, H5P_CLS_AACC, loc_id, TRUE) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTSET, H5I_INVALID_HID, "can't set access property list info")

    if(H5P_DEFAULT != lapl_id) {
        if(TRUE != H5P_isa_class(lapl_id, H5P_LINK_ACCESS))
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "not link access property list ID")
        H5CX_set_lapl(lapl_id);
    }

    /* Set up location struct */
    loc_params.type                         = H5VL_OBJECT_BY_NAME;
    loc_params.obj_type                     = H5I_get_type(loc_id);
    loc_params.loc_data.loc_by_name.name    = obj_name;
    loc_params.loc_data.loc_by_name.lapl_id = lapl_id;

    /* Get the location object */
    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid location identifier")

    /* Create the attribute */
    if(NULL == (attr = H5VL_attr_create(vol_obj, &loc_params, attr_name, type_id, space_id, acpl_id, aapl_id, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL)))
        HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, H5I_INVALID_HID, "unable to create attribute")

    /* Register the new attribute and get an ID for it */
    if((ret_value = H5VL_register(H5I_ATTR, attr, vol_obj->connector, TRUE)) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTREGISTER, H5I_INVALID_HID, "unable to atomize attribute handle")

done:
    /* Cleanup on failure */
    if(H5I_INVALID_HID == ret_value)
        if(attr && H5VL_attr_close(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) < 0)
            HDONE_ERROR(H5E_ATTR, H5E_CLOSEERROR, H5I_INVALID_HID, "can't close attribute")

    FUNC_LEAVE_API(ret_value)
} /* H5Acreate_by_name() */


/*--------------------------------------------------------------------------
 NAME
    H5Aopen
 PURPOSE
    Opens an attribute for an object by looking up the attribute name
 USAGE
    hid_t H5Aopen(loc_id, attr_name, aapl_id)
        hid_t loc_id;           IN: Object that attribute is attached to
        const char *attr_name;  IN: Name of attribute to locate and open
        hid_t aapl_id;          IN: Attribute access property list
 RETURNS
    ID of attribute on success, H5I_INVALID_HID on failure

 DESCRIPTION
        This function opens an existing attribute for access.  The attribute
    name specified is used to look up the corresponding attribute for the
    object.  The attribute ID returned from this function must be released with
    H5Aclose or resource leaks will develop.
--------------------------------------------------------------------------*/
hid_t
H5Aopen(hid_t loc_id, const char *attr_name, hid_t aapl_id)
{
    void *attr = NULL;                /* attr token from VOL connector */
    H5VL_object_t *vol_obj = NULL;        /* object token of loc_id */
    H5VL_loc_params_t loc_params; 
    hid_t ret_value = H5I_INVALID_HID;

    FUNC_ENTER_API(H5I_INVALID_HID)
    H5TRACE3("i", "i*si", loc_id, attr_name, aapl_id);

    /* Check arguments */
    if(H5I_ATTR == H5I_get_type(loc_id))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "location is not valid for an attribute")
    if(!attr_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "name parameter cannot be NULL")
    if(!*attr_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "name parameter cannot be an empty string")

    /* Verify access property list and set up collective metadata if appropriate */
    if(H5CX_set_apl(&aapl_id, H5P_CLS_AACC, loc_id, FALSE) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTSET, H5I_INVALID_HID, "can't set access property list info")

    /* Set location struct fields */
    loc_params.type         = H5VL_OBJECT_BY_SELF;
    loc_params.obj_type     = H5I_get_type(loc_id);

    /* Get the location object */
    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid location identifier")

    /* Open the attribute */
    if(NULL == (attr = H5VL_attr_open(vol_obj, &loc_params, attr_name, aapl_id, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL)))
        HGOTO_ERROR(H5E_ATTR, H5E_CANTOPENOBJ, H5I_INVALID_HID, "unable to open attribute: '%s'", attr_name)

    /* Register the attribute and get an ID for it */
    if((ret_value = H5VL_register(H5I_ATTR, attr, vol_obj->connector, TRUE)) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTREGISTER, H5I_INVALID_HID, "unable to atomize attribute handle")

done:
    /* Cleanup on failure */
    if(H5I_INVALID_HID == ret_value)
        if(attr && H5VL_attr_close(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) < 0)
            HDONE_ERROR(H5E_ATTR, H5E_CLOSEERROR, H5I_INVALID_HID, "can't close attribute")

    FUNC_LEAVE_API(ret_value)
} /* H5Aopen() */


/*--------------------------------------------------------------------------
 NAME
    H5Aopen_by_name
 PURPOSE
    Opens an attribute for an object by looking up the attribute name
 USAGE
    hid_t H5Aopen_by_name(loc_id, obj_name, attr_name, aapl_id, lapl_id)
        hid_t loc_id;           IN: Object that attribute is attached to
        const char *obj_name;   IN: Name of object relative to location
        const char *attr_name;  IN: Name of attribute to locate and open
        hid_t aapl_id;          IN: Attribute access property list
        hid_t lapl_id;          IN: Link access property list
 RETURNS
    ID of attribute on success, H5I_INVALID_HID on failure

 DESCRIPTION
        This function opens an existing attribute for access.  The attribute
    name specified is used to look up the corresponding attribute for the
    object.  The attribute ID returned from this function must be released with
    H5Aclose or resource leaks will develop.
--------------------------------------------------------------------------*/
hid_t
H5Aopen_by_name(hid_t loc_id, const char *obj_name, const char *attr_name,
    hid_t aapl_id, hid_t lapl_id)
{
    void *attr = NULL;               /* attr token from VOL connector */
    H5VL_object_t *vol_obj = NULL;       /* object token of loc_id */
    H5VL_loc_params_t loc_params;
    hid_t ret_value = H5I_INVALID_HID;

    FUNC_ENTER_API(H5I_INVALID_HID)
    H5TRACE5("i", "i*s*sii", loc_id, obj_name, attr_name, aapl_id, lapl_id);

    /* Check arguments */
    if(H5I_ATTR == H5I_get_type(loc_id))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "location is not valid for an attribute")
    if(!obj_name || !*obj_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "no object name")
    if(!attr_name || !*attr_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "no attribute name")

    /* Verify access property list and set up collective metadata if appropriate */
    if(H5CX_set_apl(&aapl_id, H5P_CLS_AACC, loc_id, FALSE) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTSET, H5I_INVALID_HID, "can't set access property list info")

    /* Set lapl_id and add to context */
    if(H5P_DEFAULT != lapl_id) {
        if(TRUE != H5P_isa_class(lapl_id, H5P_LINK_ACCESS))
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "not link access property list ID")
        H5CX_set_lapl(lapl_id);
    }
    else 
        lapl_id = H5P_LINK_ACCESS_DEFAULT;

    /* Fill in location struct fields */
    loc_params.type                         = H5VL_OBJECT_BY_NAME;
    loc_params.loc_data.loc_by_name.name    = obj_name;
    loc_params.loc_data.loc_by_name.lapl_id = lapl_id;
    loc_params.obj_type                     = H5I_get_type(loc_id);

    /* Get the location object */
    if (NULL == (vol_obj = H5VL_vol_object(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid location identifier")

    /* Open the attribute */
    if(NULL == (attr = H5VL_attr_open(vol_obj, &loc_params, attr_name, aapl_id, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL)))
        HGOTO_ERROR(H5E_ATTR, H5E_CANTOPENOBJ, H5I_INVALID_HID, "can't open attribute")

    /* Register the attribute and get an ID for it */
    if((ret_value = H5VL_register(H5I_ATTR, attr, vol_obj->connector, TRUE)) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTREGISTER, H5I_INVALID_HID, "unable to atomize attribute handle")

done:
    /* Cleanup on failure */
    if(H5I_INVALID_HID == ret_value)
        if(attr && H5VL_attr_close(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) < 0)
            HDONE_ERROR(H5E_ATTR, H5E_CLOSEERROR, H5I_INVALID_HID, "can't close attribute")

    FUNC_LEAVE_API(ret_value)
} /* end H5Aopen_by_name() */


/*--------------------------------------------------------------------------
 NAME
    H5Aopen_by_idx
 PURPOSE
    Opens the n'th attribute for an object, according to the order within
    an index
 USAGE
    hid_t H5Aopen_by_idx(loc_id, obj_ame, idx_type, order, n, aapl_id, lapl_id)
        hid_t loc_id;           IN: Object that attribute is attached to
        const char *obj_name;   IN: Name of object relative to location
        H5_index_t idx_type;    IN: Type of index to use
        H5_iter_order_t order;  IN: Order to iterate over index
        hsize_t n;              IN: Index (0-based) attribute to open
        hid_t aapl_id;          IN: Attribute access property list
        hid_t lapl_id;          IN: Link access property list
 RETURNS
    ID of attribute on success, H5I_INVALID_HID on failure

 DESCRIPTION
        This function opens an existing attribute for access.  The attribute
    index specified is used to look up the corresponding attribute for the
    object.  The attribute ID returned from this function must be released with
    H5Aclose or resource leaks will develop.
--------------------------------------------------------------------------*/
hid_t
H5Aopen_by_idx(hid_t loc_id, const char *obj_name, H5_index_t idx_type,
    H5_iter_order_t order, hsize_t n, hid_t aapl_id, hid_t lapl_id)
{
    void *attr = NULL;   /* Attribute opened */
    H5VL_object_t *vol_obj = NULL;        /* object token of loc_id */
    H5VL_loc_params_t loc_params;
    hid_t ret_value = H5I_INVALID_HID;                  /* Return value */

    FUNC_ENTER_API(H5I_INVALID_HID)
    H5TRACE7("i", "i*sIiIohii", loc_id, obj_name, idx_type, order, n, aapl_id,
             lapl_id);

    /* Check arguments */
    if(H5I_ATTR == H5I_get_type(loc_id))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "location is not valid for an attribute")
    if(!obj_name || !*obj_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "no object name")
    if(idx_type <= H5_INDEX_UNKNOWN || idx_type >= H5_INDEX_N)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "invalid index type specified")
    if(order <= H5_ITER_UNKNOWN || order >= H5_ITER_N)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "invalid iteration order specified")

    /* Verify access property list and set up collective metadata if appropriate */
    if(H5CX_set_apl(&aapl_id, H5P_CLS_AACC, loc_id, FALSE) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTSET, H5I_INVALID_HID, "can't set access property list info")

    /* Set lapl_id and add to context */
    if(H5P_DEFAULT != lapl_id) {
        if(TRUE != H5P_isa_class(lapl_id, H5P_LINK_ACCESS))
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "not link access property list ID")
        H5CX_set_lapl(lapl_id);
    }
    else 
        lapl_id = H5P_LINK_ACCESS_DEFAULT;

    /* Fill in location struct parameters */
    loc_params.type                         = H5VL_OBJECT_BY_IDX;
    loc_params.loc_data.loc_by_idx.name     = obj_name;
    loc_params.loc_data.loc_by_idx.idx_type = idx_type;
    loc_params.loc_data.loc_by_idx.order    = order;
    loc_params.loc_data.loc_by_idx.n        = n;
    loc_params.loc_data.loc_by_idx.lapl_id  = lapl_id;
    loc_params.obj_type                     = H5I_get_type(loc_id);

    /* Get the location object */
    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid location identifier")

    /* Open the attribute */
    if(NULL == (attr = H5VL_attr_open(vol_obj, &loc_params, NULL, aapl_id, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL)))
        HGOTO_ERROR(H5E_ATTR, H5E_CANTOPENOBJ, H5I_INVALID_HID, "unable to open attribute")

    /* Register the attribute and get an ID for it */
    if((ret_value = H5VL_register(H5I_ATTR, attr, vol_obj->connector, TRUE)) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTREGISTER, H5I_INVALID_HID, "unable to atomize attribute handle")

done:
    /* Cleanup on failure */
    if(H5I_INVALID_HID == ret_value)
        if(attr && H5VL_attr_close(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) < 0)
            HDONE_ERROR(H5E_ATTR, H5E_CLOSEERROR, H5I_INVALID_HID, "can't close attribute")

    FUNC_LEAVE_API(ret_value)
} /* H5Aopen_by_idx() */


/*--------------------------------------------------------------------------
 NAME
    H5Awrite
 PURPOSE
    Write out data to an attribute
 USAGE
    herr_t H5Awrite (attr_id, dtype_id, buf)
        hid_t attr_id;       IN: Attribute to write
        hid_t dtype_id;       IN: Memory datatype of buffer
        const void *buf;     IN: Buffer of data to write
 RETURNS
    Non-negative on success/Negative on failure

 DESCRIPTION
        This function writes a complete attribute to disk.
--------------------------------------------------------------------------*/
herr_t
H5Awrite(hid_t attr_id, hid_t dtype_id, const void *buf)
{
    H5VL_object_t  *vol_obj;                   /* Attribute object for ID */
    herr_t          ret_value;              /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE3("e", "ii*x", attr_id, dtype_id, buf);

    /* Check arguments */
    if(NULL == (vol_obj = (H5VL_object_t *)H5I_object_verify(attr_id, H5I_ATTR)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not an attribute")
    if(H5I_DATATYPE != H5I_get_type(dtype_id))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a datatype")
    if(NULL == buf)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "buf parameter can't be NULL")

    /* Set up collective metadata if appropriate */
    if(H5CX_set_loc(attr_id) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTSET, FAIL, "can't set collective metadata read")

    /* Write the attribute data */
    if((ret_value = H5VL_attr_write(vol_obj, dtype_id, buf, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL)) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_WRITEERROR, FAIL, "unable to write attribute")

done:
    FUNC_LEAVE_API(ret_value)
} /* H5Awrite() */


/*--------------------------------------------------------------------------
 NAME
    H5Aread
 PURPOSE
    Read in data from an attribute
 USAGE
    herr_t H5Aread (attr_id, dtype_id, buf)
        hid_t attr_id;       IN: Attribute to read
        hid_t dtype_id;       IN: Memory datatype of buffer
        void *buf;           IN: Buffer for data to read
 RETURNS
    Non-negative on success/Negative on failure

 DESCRIPTION
        This function reads a complete attribute from disk.
--------------------------------------------------------------------------*/
herr_t
H5Aread(hid_t attr_id, hid_t dtype_id, void *buf)
{
    H5VL_object_t  *vol_obj;               /* Attribute object for ID */
    herr_t          ret_value;          /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE3("e", "ii*x", attr_id, dtype_id, buf);

    /* Check arguments */
    if(NULL == (vol_obj = (H5VL_object_t *)H5I_object_verify(attr_id, H5I_ATTR)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not an attribute")
    if(H5I_DATATYPE != H5I_get_type(dtype_id))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a datatype")
    if(NULL == buf)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "buf parameter can't be NULL")

    /* Read the attribute data */
    if((ret_value = H5VL_attr_read(vol_obj, dtype_id, buf, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL)) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_READERROR, FAIL, "unable to read attribute")

done:
    FUNC_LEAVE_API(ret_value)
} /* H5Aread() */


/*--------------------------------------------------------------------------
 NAME
    H5Aget_space
 PURPOSE
    Gets a copy of the dataspace for an attribute
 USAGE
    hid_t H5Aget_space (attr_id)
        hid_t attr_id;       IN: Attribute to get dataspace of
 RETURNS
    A dataspace ID on success, H5I_INVALID_HID on failure

 DESCRIPTION
        This function retrieves a copy of the dataspace for an attribute.
    The dataspace ID returned from this function must be released with H5Sclose
    or resource leaks will develop.
--------------------------------------------------------------------------*/
hid_t
H5Aget_space(hid_t attr_id)
{
    H5VL_object_t  *vol_obj        = NULL;                 /* Attribute object for ID */
    hid_t           ret_value   = H5I_INVALID_HID;      /* Return value */

    FUNC_ENTER_API(H5I_INVALID_HID)
    H5TRACE1("i", "i", attr_id);

    /* Check arguments */
    if(NULL == (vol_obj = (H5VL_object_t *)H5I_object_verify(attr_id, H5I_ATTR)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "not an attribute")

    /* Get the dataspace */
    if(H5VL_attr_get(vol_obj, H5VL_ATTR_GET_SPACE, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &ret_value) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTGET, H5I_INVALID_HID, "unable to get dataspace of attribute")

done:
    FUNC_LEAVE_API(ret_value)
} /* H5Aget_space() */


/*--------------------------------------------------------------------------
 NAME
    H5Aget_type
 PURPOSE
    Gets a copy of the datatype for an attribute
 USAGE
    hid_t H5Aget_type (attr_id)
        hid_t attr_id;       IN: Attribute to get datatype of
 RETURNS
    A datatype ID on success, H5I_INVALID_HID on failure

 DESCRIPTION
        This function retrieves a copy of the datatype for an attribute.
    The datatype ID returned from this function must be released with H5Tclose
    or resource leaks will develop.
--------------------------------------------------------------------------*/
hid_t
H5Aget_type(hid_t attr_id)
{
    H5VL_object_t  *vol_obj = NULL;                     /* Attribute object for ID */
    hid_t           ret_value   = H5I_INVALID_HID;      /* Return value */

    FUNC_ENTER_API(H5I_INVALID_HID)
    H5TRACE1("i", "i", attr_id);

    /* Check arguments */
    if(NULL == (vol_obj = (H5VL_object_t *)H5I_object_verify(attr_id, H5I_ATTR)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "not an attribute")

    /* Get the datatype */
    if(H5VL_attr_get(vol_obj, H5VL_ATTR_GET_TYPE, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &ret_value) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTGET, H5I_INVALID_HID, "unable to get datatype of attribute")

done:
    FUNC_LEAVE_API(ret_value)
} /* H5Aget_type() */


/*--------------------------------------------------------------------------
 NAME
    H5Aget_create_plist
 PURPOSE
    Gets a copy of the creation property list for an attribute
 USAGE
    hssize_t H5Aget_create_plist (attr_id, buf_size, buf)
        hid_t attr_id;      IN: Attribute to get name of
 RETURNS
    This function returns the ID of a copy of the attribute's creation
    property list, or H5I_INVALID_HID on failure.

 ERRORS

 DESCRIPTION
        This function returns a copy of the creation property list for
    an attribute.  The resulting ID must be closed with H5Pclose() or
    resource leaks will occur.
--------------------------------------------------------------------------*/
hid_t
H5Aget_create_plist(hid_t attr_id)
{
    H5VL_object_t  *vol_obj        = NULL;                 /* Attribute object for ID */
    hid_t           ret_value   = H5I_INVALID_HID;      /* Return value */

    FUNC_ENTER_API(H5I_INVALID_HID)
    H5TRACE1("i", "i", attr_id);

    HDassert(H5P_LST_ATTRIBUTE_CREATE_ID_g != -1);

    /* Check arguments */
    if(NULL == (vol_obj = (H5VL_object_t *)H5I_object_verify(attr_id, H5I_ATTR)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "not an attribute")

    /* Get the acpl */
    if(H5VL_attr_get(vol_obj, H5VL_ATTR_GET_ACPL, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &ret_value) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTGET, H5I_INVALID_HID, "unable to get creation property list for attribute")

done:
    FUNC_LEAVE_API(ret_value)
} /* end H5Aget_create_plist() */


/*--------------------------------------------------------------------------
 NAME
    H5Aget_name
 PURPOSE
    Gets a copy of the name for an attribute
 USAGE
    hssize_t H5Aget_name (attr_id, buf_size, buf)
        hid_t attr_id;      IN: Attribute to get name of
        size_t buf_size;    IN: The size of the buffer to store the string in.
        char *buf;          IN: Buffer to store name in
 RETURNS
    This function returns the length of the attribute's name (which may be
    longer than 'buf_size') on success or negative for failure.

 DESCRIPTION
        This function retrieves the name of an attribute for an attribute ID.
    Up to 'buf_size' characters are stored in 'buf' followed by a '\0' string
    terminator.  If the name of the attribute is longer than 'buf_size'-1,
    the string terminator is stored in the last position of the buffer to
    properly terminate the string.
--------------------------------------------------------------------------*/
ssize_t
H5Aget_name(hid_t attr_id, size_t buf_size, char *buf)
{
    H5VL_object_t      *vol_obj        = NULL;             /* Attribute object for ID */
    H5VL_loc_params_t   loc_params;
    ssize_t             ret_value   = -1;

    FUNC_ENTER_API((-1))
    H5TRACE3("Zs", "iz*s", attr_id, buf_size, buf);

    /* check arguments */
    if(NULL == (vol_obj = (H5VL_object_t *)H5I_object_verify(attr_id, H5I_ATTR)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, (-1), "not an attribute")
    if(!buf && buf_size)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, (-1), "buf cannot be NULL if buf_size is non-zero")

    /* Set location struct parameters */
    loc_params.type = H5VL_OBJECT_BY_SELF;
    loc_params.obj_type = H5I_get_type(attr_id);

    /* Get the attribute name */
    if(H5VL_attr_get(vol_obj, H5VL_ATTR_GET_NAME, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &loc_params, buf_size, buf, &ret_value) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTGET, (-1), "unable to get attribute name")

done:
    FUNC_LEAVE_API(ret_value)
} /* H5Aget_name() */


/*-------------------------------------------------------------------------
 * Function:	H5Aget_name_by_idx
 *
 * Purpose:	Retrieve name of an attribute, according to the
 *		order within an index.
 *
 *              Same pattern of behavior as H5Iget_name.
 *
 * Return:	Success:	Non-negative length of name, with information
 *				in NAME buffer
 *		Failure:	Negative
 *
 * Programmer:	Quincey Koziol
 *              February  8, 2007
 *
 *-------------------------------------------------------------------------
 */
ssize_t
H5Aget_name_by_idx(hid_t loc_id, const char *obj_name, H5_index_t idx_type,
    H5_iter_order_t order, hsize_t n, char *name /*out*/, size_t size,
    hid_t lapl_id)
{
    H5VL_object_t *vol_obj;
    H5VL_loc_params_t loc_params;
    ssize_t	ret_value;      /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE8("Zs", "i*sIiIohxzi", loc_id, obj_name, idx_type, order, n, name, size,
             lapl_id);

    /* Check args */
    if(H5I_ATTR == H5I_get_type(loc_id))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "location is not valid for an attribute")
    if(!obj_name || !*obj_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no name")
    if(!name && size)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "name cannot be NULL if size is non-zero")
    if(idx_type <= H5_INDEX_UNKNOWN || idx_type >= H5_INDEX_N)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid index type specified")
    if(order <= H5_ITER_UNKNOWN || order >= H5_ITER_N)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid iteration order specified")

    /* Verify access property list and set up collective metadata if appropriate */
    if(H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, FALSE) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTSET, FAIL, "can't set access property list info")

    /* Get the object */
    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid object identifier")

    loc_params.type = H5VL_OBJECT_BY_IDX;
    loc_params.loc_data.loc_by_idx.name = obj_name;
    loc_params.loc_data.loc_by_idx.idx_type = idx_type;
    loc_params.loc_data.loc_by_idx.order = order;
    loc_params.loc_data.loc_by_idx.n = n;
    loc_params.loc_data.loc_by_idx.lapl_id = lapl_id;
    loc_params.obj_type = H5I_get_type(loc_id);

    /* Get the name */
    if(H5VL_attr_get(vol_obj, H5VL_ATTR_GET_NAME, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &loc_params, size, name, &ret_value) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTGET, FAIL, "unable to get name")

done:
    FUNC_LEAVE_API(ret_value)
} /* end H5Aget_name_by_idx() */


/*-------------------------------------------------------------------------
 * Function:	H5Aget_storage_size
 *
 * Purpose:	Returns the amount of storage size that is required for this
 *		attribute.
 *
 * Return:	Success:	The amount of storage size allocated for the
 *				attribute.  The return value may be zero
 *                              if no data has been stored.
 *
 *		Failure:	Zero
 *
 * Programmer:	Raymond Lu
 *              October 23, 2002
 *
 *-------------------------------------------------------------------------
 */
hsize_t
H5Aget_storage_size(hid_t attr_id)
{
    H5VL_object_t *vol_obj;
    hsize_t	ret_value;      /* Return value */

    FUNC_ENTER_API(0)
    H5TRACE1("h", "i", attr_id);

    /* Check arguments */
    if(NULL == (vol_obj = (H5VL_object_t *)H5I_object_verify(attr_id, H5I_ATTR)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, 0, "not an attribute")

    /* Get the storage size */
    if(H5VL_attr_get(vol_obj, H5VL_ATTR_GET_STORAGE_SIZE, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &ret_value) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTGET, 0, "unable to get acpl")

done:
    FUNC_LEAVE_API(ret_value)
} /* end H5Aget_storage_size() */


/*-------------------------------------------------------------------------
 * Function:	H5Aget_info
 *
 * Purpose:	Retrieve information about an attribute.
 *
 * Return:	Success:	Non-negative
 *		Failure:	Negative
 *
 * Programmer:	Quincey Koziol
 *              February  6, 2007
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Aget_info(hid_t attr_id, H5A_info_t *ainfo)
{
    H5VL_object_t *vol_obj;
    H5VL_loc_params_t loc_params;
    herr_t	ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE2("e", "i*x", attr_id, ainfo);

    /* Check arguments */
    if(NULL == (vol_obj = (H5VL_object_t *)H5I_object_verify(attr_id, H5I_ATTR)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not an attribute")
    if(!ainfo)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "attribute_info parameter cannot be NULL")

    loc_params.type = H5VL_OBJECT_BY_SELF;
    loc_params.obj_type = H5I_get_type(attr_id);

    /* Get the attribute information */
    if(H5VL_attr_get(vol_obj, H5VL_ATTR_GET_INFO, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &loc_params, ainfo) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTGET, FAIL, "unable to get attribute info")

done:
    FUNC_LEAVE_API(ret_value)
} /* end H5Aget_info() */


/*-------------------------------------------------------------------------
 * Function:	H5Aget_info_by_name
 *
 * Purpose:	Retrieve information about an attribute by name.
 *
 * Return:	Success:	Non-negative
 *		Failure:	Negative
 *
 * Programmer:	Quincey Koziol
 *              February  6, 2007
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Aget_info_by_name(hid_t loc_id, const char *obj_name, const char *attr_name,
    H5A_info_t *ainfo, hid_t lapl_id)
{
    H5VL_object_t *vol_obj;
    H5VL_loc_params_t   loc_params;
    herr_t	ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE5("e", "i*s*s*xi", loc_id, obj_name, attr_name, ainfo, lapl_id);

    /* Check args */
    if(H5I_ATTR == H5I_get_type(loc_id))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "location is not valid for an attribute")
    if(!obj_name || !*obj_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no object name")
    if(!attr_name || !*attr_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no attribute name")
    if(NULL == ainfo)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid info pointer")

    /* Verify access property list and set up collective metadata if appropriate */
    if(H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, FALSE) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTSET, FAIL, "can't set access property list info")

    loc_params.type = H5VL_OBJECT_BY_NAME;
    loc_params.loc_data.loc_by_name.name = obj_name;
    loc_params.loc_data.loc_by_name.lapl_id = lapl_id;
    loc_params.obj_type = H5I_get_type(loc_id);

    /* Get the object */
    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid object identifier")

    /* Get the attribute information */
    if(H5VL_attr_get(vol_obj, H5VL_ATTR_GET_INFO, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &loc_params, ainfo, attr_name) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTGET, FAIL, "unable to get attribute info")

done:
    FUNC_LEAVE_API(ret_value)
} /* end H5Aget_info_by_name() */


/*-------------------------------------------------------------------------
 * Function:	H5Aget_info_by_idx
 *
 * Purpose:	Retrieve information about an attribute, according to the
 *		order within an index.
 *
 * Return:	Success:	Non-negative with information in AINFO
 *		Failure:	Negative
 *
 * Programmer:	Quincey Koziol
 *              February  8, 2007
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Aget_info_by_idx(hid_t loc_id, const char *obj_name, H5_index_t idx_type,
    H5_iter_order_t order, hsize_t n, H5A_info_t *ainfo, hid_t lapl_id)
{
    H5VL_object_t *vol_obj;
    H5VL_loc_params_t   loc_params;
    herr_t	ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE7("e", "i*sIiIoh*xi", loc_id, obj_name, idx_type, order, n, ainfo,
             lapl_id);

    /* Check args */
    if(H5I_ATTR == H5I_get_type(loc_id))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "location is not valid for an attribute")
    if(!obj_name || !*obj_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no name")
    if(idx_type <= H5_INDEX_UNKNOWN || idx_type >= H5_INDEX_N)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid index type specified")
    if(order <= H5_ITER_UNKNOWN || order >= H5_ITER_N)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid iteration order specified")
    if(NULL == ainfo)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid info pointer")

    /* Verify access property list and set up collective metadata if appropriate */
    if(H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, FALSE) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTSET, FAIL, "can't set access property list info")

    loc_params.type                         = H5VL_OBJECT_BY_IDX;
    loc_params.loc_data.loc_by_idx.name     = obj_name;
    loc_params.loc_data.loc_by_idx.idx_type = idx_type;
    loc_params.loc_data.loc_by_idx.order    = order;
    loc_params.loc_data.loc_by_idx.n        = n;
    loc_params.loc_data.loc_by_idx.lapl_id  = lapl_id;
    loc_params.obj_type                     = H5I_get_type(loc_id);

    /* Get the object */
    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid object identifier")

    /* Get the attribute information */
    if(H5VL_attr_get(vol_obj, H5VL_ATTR_GET_INFO, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &loc_params, ainfo) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTGET, FAIL, "unable to get attribute info")

done:
    FUNC_LEAVE_API(ret_value)
} /* end H5Aget_info_by_idx() */


/*-------------------------------------------------------------------------
 * Function:    H5Arename
 *
 * Purpose:     Rename an attribute
 *
 * Return:      SUCCEED/FAIL
 *
 * Programmer:	Raymond Lu
 *              October 23, 2002
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Arename(hid_t loc_id, const char *old_name, const char *new_name)
{
    herr_t	ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE3("e", "i*s*s", loc_id, old_name, new_name);

    /* check arguments */
    if(H5I_ATTR == H5I_get_type(loc_id))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "location is not valid for an attribute")
    if(!old_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "old attribute name cannot be NULL")
    if(!*old_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "old attribute name cannot be an empty string")
    if(!new_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "new attribute name cannot be NULL")
    if(!*new_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "new attribute name cannot be an empty string")

    /* Avoid thrashing things if the names are the same */
    if(HDstrcmp(old_name, new_name)) {
        H5VL_object_t *vol_obj;
        H5VL_loc_params_t loc_params;

        loc_params.type = H5VL_OBJECT_BY_SELF;
        loc_params.obj_type = H5I_get_type(loc_id);

        /* Get the location object */
        if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")

        /* Set up collective metadata if appropriate */
        if(H5CX_set_loc(loc_id) < 0)
            HGOTO_ERROR(H5E_ATTR, H5E_CANTSET, FAIL, "can't set collective metadata read")

        /* Rename the attribute */
        if(H5VL_attr_specific(vol_obj, &loc_params, H5VL_ATTR_RENAME, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, old_name, new_name) < 0)
            HGOTO_ERROR(H5E_ATTR, H5E_CANTRENAME, FAIL, "can't rename attribute")
    } /* end if */

done:
    FUNC_LEAVE_API(ret_value)
} /* H5Arename() */


/*-------------------------------------------------------------------------
 * Function:    H5Arename_by_name
 *
 * Purpose:     Rename an attribute
 *
 * Return:      SUCCEED/FAIL
 *
 * Programmer:	Quincey Koziol
 *              February 20, 2007
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Arename_by_name(hid_t loc_id, const char *obj_name, const char *old_attr_name,
    const char *new_attr_name, hid_t lapl_id)
{
    herr_t	ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE5("e", "i*s*s*si", loc_id, obj_name, old_attr_name, new_attr_name,
             lapl_id);

    /* check arguments */
    if(H5I_ATTR == H5I_get_type(loc_id))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "location is not valid for an attribute")
    if(!obj_name || !*obj_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no object name")
    if(!old_attr_name || !*old_attr_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no old attribute name")
    if(!new_attr_name || !*new_attr_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no new attribute name")

    /* Avoid thrashing things if the names are the same */
    if(HDstrcmp(old_attr_name, new_attr_name)) {
        H5VL_object_t *vol_obj;
        H5VL_loc_params_t loc_params;

        /* Verify access property list and set up collective metadata if appropriate */
        if(H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, TRUE) < 0)
            HGOTO_ERROR(H5E_ATTR, H5E_CANTSET, FAIL, "can't set access property list info")

        loc_params.type = H5VL_OBJECT_BY_NAME;
        loc_params.loc_data.loc_by_name.name = obj_name;
        loc_params.loc_data.loc_by_name.lapl_id = lapl_id;
        loc_params.obj_type = H5I_get_type(loc_id);

        /* Get the location object */
        if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")

        /* Rename the attribute */
        if(H5VL_attr_specific(vol_obj, &loc_params, H5VL_ATTR_RENAME, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, old_attr_name, new_attr_name) < 0)
            HGOTO_ERROR(H5E_ATTR, H5E_CANTRENAME, FAIL, "can't rename attribute")
    } /* end if */

done:
    FUNC_LEAVE_API(ret_value)
} /* H5Arename_by_name() */


/*--------------------------------------------------------------------------
 NAME
    H5Aiterate2
 PURPOSE
    Calls a user's function for each attribute on an object
 USAGE
    herr_t H5Aiterate2(loc_id, idx_type, order, idx, op, op_data)
        hid_t loc_id;           IN: Base location for object
        H5_index_t idx_type;    IN: Type of index to use
        H5_iter_order_t order;  IN: Order to iterate over index
        hsize_t *idx;           IN/OUT: Starting (IN) & Ending (OUT) attribute
                                    in index & order
        H5A_operator2_t op;     IN: User's function to pass each attribute to
        void *op_data;          IN/OUT: User's data to pass through to iterator
                                    operator function
 RETURNS
        Returns a negative value if an error occurs, the return value of the
    last operator if it was non-zero (which can be a negative value), or zero
    if all attributes were processed.

 DESCRIPTION
        This function interates over the attributes of dataset or group
    specified with 'loc_id' & 'obj_name'.  For each attribute of the object,
    the 'op_data' and some additional information (specified below) are passed
    to the 'op' function.  The iteration begins with the '*idx'
    object in the group and the next attribute to be processed by the operator
    is returned in '*idx'.
        The operation receives the ID for the group or dataset being iterated
    over ('loc_id'), the name of the current attribute about the object
    ('attr_name'), the attribute's "info" struct ('ainfo') and the pointer to
    the operator data passed in to H5Aiterate2 ('op_data').  The return values
    from an operator are:
        A. Zero causes the iterator to continue, returning zero when all
            attributes have been processed.
        B. Positive causes the iterator to immediately return that positive
            value, indicating short-circuit success.  The iterator can be
            restarted at the next attribute.
        C. Negative causes the iterator to immediately return that value,
            indicating failure.  The iterator can be restarted at the next
            attribute.
--------------------------------------------------------------------------*/
herr_t
H5Aiterate2(hid_t loc_id, H5_index_t idx_type, H5_iter_order_t order,
    hsize_t *idx, H5A_operator2_t op, void *op_data)
{
    H5VL_object_t *vol_obj = NULL;        /* object token of loc_id */
    H5VL_loc_params_t loc_params;
    herr_t	ret_value;      /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE6("e", "iIiIo*hx*x", loc_id, idx_type, order, idx, op, op_data);

    /* check arguments */
    if(H5I_ATTR == H5I_get_type(loc_id))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "location is not valid for an attribute")
    if(idx_type <= H5_INDEX_UNKNOWN || idx_type >= H5_INDEX_N)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid index type specified")
    if(order <= H5_ITER_UNKNOWN || order >= H5_ITER_N)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid iteration order specified")

    loc_params.type = H5VL_OBJECT_BY_SELF;
    loc_params.obj_type = H5I_get_type(loc_id);

    /* get the loc object */
    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")

    /* Iterate over attributes */
    if((ret_value = H5VL_attr_specific(vol_obj, &loc_params, H5VL_ATTR_ITER, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, (int)idx_type, (int)order, idx, op, op_data)) < 0)
        HERROR(H5E_ATTR, H5E_BADITER, "error iterating over attributes");

done:
    FUNC_LEAVE_API(ret_value)
} /* H5Aiterate2() */


/*--------------------------------------------------------------------------
 NAME
    H5Aiterate_by_name
 PURPOSE
    Calls a user's function for each attribute on an object
 USAGE
    herr_t H5Aiterate2(loc_id, obj_name, idx_type, order, idx, op, op_data, lapl_id)
        hid_t loc_id;           IN: Base location for object
        const char *obj_name;   IN: Name of object relative to location
        H5_index_t idx_type;    IN: Type of index to use
        H5_iter_order_t order;  IN: Order to iterate over index
        hsize_t *idx;           IN/OUT: Starting (IN) & Ending (OUT) attribute
                                    in index & order
        H5A_operator2_t op;     IN: User's function to pass each attribute to
        void *op_data;          IN/OUT: User's data to pass through to iterator
                                    operator function
        hid_t lapl_id;          IN: Link access property list
 RETURNS
        Returns a negative value if an error occurs, the return value of the
    last operator if it was non-zero (which can be a negative value), or zero
    if all attributes were processed.

 DESCRIPTION
        This function interates over the attributes of dataset or group
    specified with 'loc_id' & 'obj_name'.  For each attribute of the object,
    the 'op_data' and some additional information (specified below) are passed
    to the 'op' function.  The iteration begins with the '*idx'
    object in the group and the next attribute to be processed by the operator
    is returned in '*idx'.
        The operation receives the ID for the group or dataset being iterated
    over ('loc_id'), the name of the current attribute about the object
    ('attr_name'), the attribute's "info" struct ('ainfo') and the pointer to
    the operator data passed in to H5Aiterate_by_name ('op_data').  The return values
    from an operator are:
        A. Zero causes the iterator to continue, returning zero when all
            attributes have been processed.
        B. Positive causes the iterator to immediately return that positive
            value, indicating short-circuit success.  The iterator can be
            restarted at the next attribute.
        C. Negative causes the iterator to immediately return that value,
            indicating failure.  The iterator can be restarted at the next
            attribute.
--------------------------------------------------------------------------*/
herr_t
H5Aiterate_by_name(hid_t loc_id, const char *obj_name, H5_index_t idx_type,
    H5_iter_order_t order, hsize_t *idx, H5A_operator2_t op, void *op_data,
    hid_t lapl_id)
{
    H5VL_object_t *vol_obj = NULL;        /* object token of loc_id */
    H5VL_loc_params_t loc_params;
    herr_t   ret_value = SUCCEED;      /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE8("e", "i*sIiIo*hx*xi", loc_id, obj_name, idx_type, order, idx, op,
             op_data, lapl_id);

    /* check arguments */
    if(H5I_ATTR == H5I_get_type(loc_id))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "location is not valid for an attribute")
    if(!obj_name || !*obj_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no object name")
    if(idx_type <= H5_INDEX_UNKNOWN || idx_type >= H5_INDEX_N)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid index type specified")
    if(order <= H5_ITER_UNKNOWN || order >= H5_ITER_N)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid iteration order specified")

    /* Verify access property list and set up collective metadata if appropriate */
    if(H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, FALSE) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTSET, FAIL, "can't set access property list info")

    loc_params.type = H5VL_OBJECT_BY_NAME;
    loc_params.obj_type = H5I_get_type(loc_id);
    loc_params.loc_data.loc_by_name.name = obj_name;
    loc_params.loc_data.loc_by_name.lapl_id = lapl_id;

    /* get the loc object */
    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")

    /* Iterate over attributes */
    if((ret_value = H5VL_attr_specific(vol_obj, &loc_params, H5VL_ATTR_ITER, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, (int)idx_type, (int)order, idx, op, op_data)) < 0)
        HERROR(H5E_ATTR, H5E_BADITER, "attribute iteration failed");

done:
    FUNC_LEAVE_API(ret_value)
} /* H5Aiterate_by_name() */


/*--------------------------------------------------------------------------
 NAME
    H5Adelete
 PURPOSE
    Deletes an attribute from a location
 USAGE
    herr_t H5Adelete(loc_id, name)
        hid_t loc_id;       IN: Object (dataset or group) to have attribute deleted from
        const char *name;   IN: Name of attribute to delete
 RETURNS
    Non-negative on success/Negative on failure
 DESCRIPTION
    This function removes the named attribute from a dataset or group.
--------------------------------------------------------------------------*/
herr_t
H5Adelete(hid_t loc_id, const char *name)
{
    H5VL_object_t      *vol_obj = NULL;
    H5VL_loc_params_t   loc_params;
    herr_t	            ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE2("e", "i*s", loc_id, name);

    /* Check arguments */
    if(H5I_ATTR == H5I_get_type(loc_id))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "location is not valid for an attribute")
    if(!name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "name parameter cannot be NULL")
    if(!*name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "name parameter cannot be an empty string")

    /* Set up collective metadata if appropriate */
    if(H5CX_set_loc(loc_id) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTSET, FAIL, "can't set collective metadata read")

    /* Fill in location struct fields */
    loc_params.type         = H5VL_OBJECT_BY_SELF;
    loc_params.obj_type     = H5I_get_type(loc_id);

    /* Get the object */
    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid object identifier")

    /* Delete the attribute */
    if(H5VL_attr_specific(vol_obj, &loc_params, H5VL_ATTR_DELETE, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, name) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTDELETE, FAIL, "unable to delete attribute")

done:
    FUNC_LEAVE_API(ret_value)
} /* H5Adelete() */


/*--------------------------------------------------------------------------
 NAME
    H5Adelete_by_name
 PURPOSE
    Deletes an attribute from a location
 USAGE
    herr_t H5Adelete_by_name(loc_id, obj_name, attr_name, lapl_id)
        hid_t loc_id;           IN: Base location for object
        const char *obj_name;   IN: Name of object relative to location
        const char *attr_name;  IN: Name of attribute to delete
        hid_t lapl_id;          IN: Link access property list
 RETURNS
    Non-negative on success/Negative on failure
 DESCRIPTION
    This function removes the named attribute from an object.
--------------------------------------------------------------------------*/
herr_t
H5Adelete_by_name(hid_t loc_id, const char *obj_name, const char *attr_name,
    hid_t lapl_id)
{
    H5VL_object_t *vol_obj;
    H5VL_loc_params_t loc_params;
    herr_t	ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE4("e", "i*s*si", loc_id, obj_name, attr_name, lapl_id);

    /* Check arguments */
    if(H5I_ATTR == H5I_get_type(loc_id))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "location is not valid for an attribute")
    if(!obj_name || !*obj_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no object name")
    if(!attr_name || !*attr_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no attribute name")

    /* Verify access property list and set up collective metadata if appropriate */
    if(H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, TRUE) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTSET, FAIL, "can't set access property list info")

    /* Fill in location struct fields */
    loc_params.type                         = H5VL_OBJECT_BY_NAME;
    loc_params.loc_data.loc_by_name.name    = obj_name;
    loc_params.loc_data.loc_by_name.lapl_id = lapl_id;
    loc_params.obj_type                     = H5I_get_type(loc_id);

    /* Get the object */
    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid object identifier")

    /* Delete the attribute */
    if(H5VL_attr_specific(vol_obj, &loc_params, H5VL_ATTR_DELETE, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, attr_name) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTDELETE, FAIL, "unable to delete attribute")

done:
    FUNC_LEAVE_API(ret_value)
} /* H5Adelete_by_name() */


/*--------------------------------------------------------------------------
 NAME
    H5Adelete_by_idx
 PURPOSE
    Deletes an attribute from a location, according to the order within an index
 USAGE
    herr_t H5Adelete_by_idx(loc_id, obj_name, idx_type, order, n, lapl_id)
        hid_t loc_id;           IN: Base location for object
        const char *obj_name;   IN: Name of object relative to location
        H5_index_t idx_type;    IN: Type of index to use
        H5_iter_order_t order;  IN: Order to iterate over index
        hsize_t n;              IN: Offset within index
        hid_t lapl_id;          IN: Link access property list
 RETURNS
    Non-negative on success/Negative on failure
 DESCRIPTION
        This function removes an attribute from an object, using the IDX_TYPE
    index to delete the N'th attribute in ORDER direction in the index.  The
    object is specified relative to the LOC_ID with the OBJ_NAME path.  To
    remove an attribute on the object specified by LOC_ID, pass in "." for
    OBJ_NAME.  The link access property list, LAPL_ID, controls aspects of
    the group hierarchy traversal when using the OBJ_NAME to locate the final
    object to operate on.
--------------------------------------------------------------------------*/
herr_t
H5Adelete_by_idx(hid_t loc_id, const char *obj_name, H5_index_t idx_type,
    H5_iter_order_t order, hsize_t n, hid_t lapl_id)
{
    H5VL_object_t *vol_obj;
    H5VL_loc_params_t loc_params;
    herr_t	ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE6("e", "i*sIiIohi", loc_id, obj_name, idx_type, order, n, lapl_id);

    /* check arguments */
    if(H5I_ATTR == H5I_get_type(loc_id))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "location is not valid for an attribute")
    if(!obj_name || !*obj_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no object name")
    if(idx_type <= H5_INDEX_UNKNOWN || idx_type >= H5_INDEX_N)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid index type specified")
    if(order <= H5_ITER_UNKNOWN || order >= H5_ITER_N)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid iteration order specified")

    /* Verify access property list and set up collective metadata if appropriate */
    if(H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, TRUE) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTSET, FAIL, "can't set access property list info")

    loc_params.type = H5VL_OBJECT_BY_IDX;
    loc_params.loc_data.loc_by_idx.name = obj_name;
    loc_params.loc_data.loc_by_idx.idx_type = idx_type;
    loc_params.loc_data.loc_by_idx.order = order;
    loc_params.loc_data.loc_by_idx.n = n;
    loc_params.loc_data.loc_by_idx.lapl_id = lapl_id;
    loc_params.obj_type = H5I_get_type(loc_id);

    /* get the object */
    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid object identifier")

    /* Delete the attribute through the VOL */
    if(H5VL_attr_specific(vol_obj, &loc_params, H5VL_ATTR_DELETE, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, NULL) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTDELETE, FAIL, "unable to delete attribute")

done:
    FUNC_LEAVE_API(ret_value)
} /* H5Adelete_by_idx() */


/*-------------------------------------------------------------------------
 * Function:    H5Aclose
 *
 * Purpose:     Closes access to an attribute and releases resources used by
 *              it. It is illegal to subsequently use that same dataset
 *              ID in calls to other attribute functions.
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Aclose(hid_t attr_id)
{
    herr_t ret_value = SUCCEED;   /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE1("e", "i", attr_id);

    /* Check arguments */
    if(NULL == H5I_object_verify(attr_id, H5I_ATTR))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not an attribute")

    /* Decrement references to that atom (and close it) */
    if(H5I_dec_app_ref(attr_id) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTDEC, FAIL, "can't close attribute")

done:
    FUNC_LEAVE_API(ret_value)
} /* H5Aclose() */


/*-------------------------------------------------------------------------
 * Function:	H5Aexists
 *
 * Purpose:	Checks if an attribute with a given name exists on an opened
 *              object.
 *
 * Return:	Success:	TRUE/FALSE
 * 		Failure:	Negative
 *
 * Programmer:	Quincey Koziol
 *              Thursday, November 1, 2007
 *
 *-------------------------------------------------------------------------
 */
htri_t
H5Aexists(hid_t obj_id, const char *attr_name)
{
    H5VL_object_t *vol_obj;
    H5VL_loc_params_t loc_params;
    htri_t	ret_value;              /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE2("t", "i*s", obj_id, attr_name);

    /* Check arguments */
    if(H5I_ATTR == H5I_get_type(obj_id))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "location is not valid for an attribute")
    if(!attr_name || !*attr_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no attribute name")

    /* get the object */
    if(NULL == (vol_obj = H5VL_vol_object(obj_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid object identifier")

    loc_params.type = H5VL_OBJECT_BY_SELF;
    loc_params.obj_type = H5I_get_type(obj_id);

    /* Check if the attribute exists */
    if(H5VL_attr_specific(vol_obj, &loc_params, H5VL_ATTR_EXISTS, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, attr_name, &ret_value) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTGET, FAIL, "unable to determine if attribute exists")

done:
    FUNC_LEAVE_API(ret_value)
} /* H5Aexists() */


/*-------------------------------------------------------------------------
 * Function:	H5Aexists_by_name
 *
 * Purpose:	Checks if an attribute with a given name exists on an object.
 *
 * Return:	Success:	TRUE/FALSE
 * 		Failure:	Negative
 *
 * Programmer:	Quincey Koziol
 *              Thursday, November 1, 2007
 *
 *-------------------------------------------------------------------------
 */
htri_t
H5Aexists_by_name(hid_t loc_id, const char *obj_name, const char *attr_name,
    hid_t lapl_id)
{
    H5VL_object_t *vol_obj;
    H5VL_loc_params_t loc_params;
    htri_t	ret_value;              /* Return value */

    FUNC_ENTER_API(FAIL)
    H5TRACE4("t", "i*s*si", loc_id, obj_name, attr_name, lapl_id);

    /* check arguments */
    if(H5I_ATTR == H5I_get_type(loc_id))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "location is not valid for an attribute")
    if(!obj_name || !*obj_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no object name")
    if(!attr_name || !*attr_name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no attribute name")

    /* Verify access property list and set up collective metadata if appropriate */
    if(H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, FALSE) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTSET, FAIL, "can't set access property list info")

    /* get the object */
    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid object identifier")

    loc_params.type = H5VL_OBJECT_BY_NAME;
    loc_params.loc_data.loc_by_name.name = obj_name;
    loc_params.loc_data.loc_by_name.lapl_id = lapl_id;
    loc_params.obj_type = H5I_get_type(loc_id);

    /* Check existence of attribute */
    if(H5VL_attr_specific(vol_obj, &loc_params, H5VL_ATTR_EXISTS, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, attr_name, &ret_value) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTGET, FAIL, "unable to determine if attribute exists")

done:
    FUNC_LEAVE_API(ret_value)
} /* H5Aexists_by_name() */