is there any api documentation for this library

[demon-bixia]

Is there any API documentation for this library or an example i can study ?
and can this library be used in another application ?

[jrose-signal]

A longstanding lack indeed. I'm going to consolidate this with #152, filed quite a while ago, which talks about some reasons why we haven't had proper documentation (not all of them still relevant). But I would guess the documentation that's needed most is at least moderately high-level, showing how the various APIs work together, rather than the basic "doc comments on every API". And that documentation should be written for all four of libsignal's languages: Java, Swift, TypeScript, and Rust. And Signal is a small org and supporting this library for clients outside of Signal is, I'm afraid, not a top priority.

(Improving the doc comments of the Rust API specifically is tracked in #467, which I'm very grateful to @cosmicexplorer for spearheading even though they don't even work at Signal! I owe them more reviews.)

[jrose-signal]

P.S. Please feel free to ask specific questions in the Development section of the unofficial community forums. It's not a replacement for real documentation but it is there.