Inserting custom property into dapl list


#1

When inserting temporary property with H5Pinsert2(dapl_id, ...) into hid_t dapl_id and checking its existence with H5Pexist( dapl_id, ... ) I get confirmed response.

However when passing this dapl_id to hid_t ds = H5Dopen(fd, "some_dataset", dapl_id); then retrieving data access property dapl_ with H5Dget_access_plist() from the returned descriptor ds I get negative response.

OTOH when I copy property into the dapl_ newly retrieved directly from dataset, I get positive response, but the copy_callback(...) function specified to H5Pinsert2(...) doesn’t get called.

My interpretation of temporary properties that they have the lifespan of the property list, in this case dapl_id.
The goal is to have a custom property with lifespan of the property list.

What am I doing wrong?
SSCCE added:

#include <iostream>
#include <hdf5.h>

#define CUSTOM_PROP "custom propery"

namespace exp {

	struct custom_prop_t {
		custom_prop_t(){ std::cout <<"<CTOR>"; }
		~custom_prop_t(){ std::cout <<"<DTOR>"; }
	};


	herr_t dapl_custom_prop_create( const char *name, size_t size, void *initial_value){
		std::cout <<"<prop create>\n";
		return 1;
	}
	herr_t dapl_custom_prop_set( ::hid_t dapl_id, const char *name, size_t size, void *new_value){
		std::cout <<"<prop set>\n";
		return 1;
	}
	herr_t dapl_custom_prop_get( ::hid_t dapl_id, const char *name, size_t size, void *value){
		return 1;
	}
	herr_t dapl_custom_prop_delete( ::hid_t dapl_id, const char *name, size_t size, void *value){
		std::cout << "<prop delete>\n";
		return 1;
	}
	herr_t dapl_custom_prop_copy( const char *name, size_t size, void *value){
		std::cout <<"<prop copy>\n";
		return 1;
	}
	int dapl_custom_prop_comp( const void *value1, const void *value2, size_t size){
		std::cout << "<prop comp>\n";
		return 1;
	}

	herr_t dapl_custom_prop_close( const char *name, size_t size, void *ptr ){
		delete *static_cast<exp::custom_prop_t**>( ptr );
		return 1;
	}

	::herr_t dapl_custom_prop(::hid_t dapl ){
		exp::custom_prop_t* ptr = new exp::custom_prop_t();
		return H5Pinsert2(dapl, CUSTOM_PROP, sizeof(exp::custom_prop_t*), &ptr,
				dapl_custom_prop_set, dapl_custom_prop_get, dapl_custom_prop_delete, dapl_custom_prop_copy, dapl_custom_prop_comp, dapl_custom_prop_close);
	}

}


int main(int argc, char **argv) {
	std::cout << "\n\n";

	std::cout << "creating dapl_0 and dapl_1: \n";
	hid_t dapl_0 = H5Pcreate( H5P_DATASET_ACCESS );
	hid_t dapl_1 = H5Pcreate( H5P_DATASET_ACCESS );

	std::cout << "inserting custom property into dapl_0, expecting <CTOR> being called: \n";
	herr_t err =  exp::dapl_custom_prop( dapl_0 );
	std::cout << "status (herr_t) < 0 => error :  " << err <<"\n";

	std::cout << "checking the existence of custom prop in dapl_0:\n";
	if( H5Pexist(dapl_0, CUSTOM_PROP) ){
		std::cout<<"<dapl_0 custom prop present>\n";
	}else{
		std::cout<<"<dapl_0 custom prop NOT present>\n";
	}

	std::cout<< "copying custom prop from dapl_0 to dapl_1, expecting copy callback should be called:\n";
	H5Pcopy_prop(dapl_1, dapl_0, CUSTOM_PROP );
	std::cout<<"";
	std::cout << "\n\n";

	return 0;
}


#2

Solution: Only H5Pcopy( ... ) will trigger property copy callback, which I overlooked in the documentation.