http://www.perlmonks.org?node_id=1049271


in reply to Not able to pass the hash reference to callback from xsubpp

Subs can only take scalars as arguments; you can't pass a hash. You can pass a reference to the hash, though.

Also, you hold two references to the hash for no reason.

You want

HV* data_hash = newHV(); SV* data_hash_ref = newRV_inc(data_hash); ... call_perl_sub("test_callback", data_hash_ref); ... SvREFCNT_dec(data_hash_ref); /* Or motalise and return to caller */ SvREFCNT_dec(data_hash);

Since we know data_hash_ref will outlive data_hash, we can avoid a ref count increment and decrement pair and simplify the above to the following:

HV* data_hash = newHV(); SV* data_hash_ref = newRV_noinc(data_hash); ... call_perl_sub("test_callback", data_hash_ref); ... SvREFCNT_dec(data_hash_ref); /* Or motalise and return to caller */