atomvm
question: howto return a void* from a nif.
hello,
what would be the best way to return a void* (which will be an input parameter of other nif(s) ) from a nif?
thanks for any answer.
Same with BEAM, the best is to create a resource if void* is a malloc zone that needs to be freed when it's no longer referenced, otherwise you would risk a leak.
Resources are ref counted and destructor is called when the reference counter reaches 0.
Resources in AtomVM currently appear as zero-length binaries as it used to do with BEAM OTP21. This is a limitation because I wasn't aware of resources as references that were introduced later in BEAM and we need to catch up as references are superior for matching. Meanwhile you might need a reference to distinguish resources.
thanks for your answer,
memory leaks are not a problem in my use case because resources are allocated at startup and will live 'forever'. the void* points to an object of an unknown structure which would have to be destroyed - a simple free is not enough. in order to call the destructor i would implement a nif which would call the destructor, use a try - catch - after construct and call the destructing nif in the after block.
anyway ..
how would i retrieve the void* from a resource? what would be the 'term function'?
e.
If you have NIF that takes a resource reference, you can use enif_get_resource, cast it, and extract your data from the registered struct.
