search

sccn / liblsl

C++ lsl library for multi-modal time-synched data transmission over the local network
Other
108 stars 63 forks source link

Add C++ API function to retrieve the opaque C API handles #105

Closed tstenner closed 3 years ago

tstenner commented 3 years ago

I recently had a situation where I had to push some non-zero terminated strings with known lengths to an outlet with a regular sampling rate, so I only had one timestamp.

The C API had int32_t lsl_push_chunk_buft(lsl_outlet out, const char **data, const uint32_t *lengths, unsigned long data_elements, double timestamp), but it wasn't wrapped in the C++ API and I didn't want to give up the niceties the C++ API offered.

This PR adds a function raw_lsl_ptr to both the stream outlet and inlet so the plain C API functions can be called without having to rewrite everything to use the C API.

cboulay commented 3 years ago

Without testing myself, if a user keeps a reference to the raw handle while the outlet is destructed (which calls lsl_destroy_outlet(obj) wherein delete obj; is called) then I guess there will be some undesirable behaviour. I suppose you could add a note in the comments to warn about this, but at the same time I think there's some implied danger when grabbing raw handles.

The PR looks good to me.

tstenner commented 3 years ago

Without testing myself, if a user keeps a reference to the raw handle while the outlet is destructed (which calls lsl_destroy_outlet(obj) wherein delete obj; is called) then I guess there will be some undesirable behaviour.

Absolutely. The only sane way to fix this is to require C++11 and wrap the pointer in a shared_ptr, see #106.

tstenner commented 3 years ago

Thanks to @cboulay #106 has been merged and this PR is trivial, so I'm merging this.