nimbus-eth1/wrappers/README.md

This folder contains an experimental C wrapper for using parts of the Nimbus
code from C/Go in the Status console client:

https://github.com/status-im/status-console-client/

It serves mainly as a proof-of-concept for now - there are several unresolved
issues surrounding threading, inter-language communication, callbacks etc.

To build the wrappers and the example programs, run from the top level directory:

```bash
make wrappers
```

Now you can run the example programs:

```bash
build/C_wrapper_example
build/go_wrapper_example
build/go_wrapper_whisper_example
```

To build statically linked versions:

```bash
make wrappers-static
```

# Notes on usage
Before any of the API calls are done, `NimMain()` needs to be run.

After this any of the asymmetric or symmetric keys API calls can be done.

Before any actual Whisper calls are done, `nimbus_start()` needs to be called.
This will setup the Whisper node, start discovery and connect to the Status
fleet.

After this call you can use the Whisper related calls such as
`nimbus_subscribe_filter` and `nimbus_post`.

`nimbus_subscribe_filter` allows you to pass a pointer to user data. This will
just pass the pointer to the, by you provided, callback. You can use this to
have a certain context in the callback.

Be aware that when using this with cgo, you will have a problem when passing a
Go pointer that contains other Go pointers, as this is no longer allowed.
See also: https://golang.org/cmd/cgo/#hdr-Passing_pointers

This can be resolved by refering to it indirectly, e.g. using a map in Go
containing the pointers. See here for an example solution:
https://github.com/mattn/go-pointer/blob/master/pointer.go