Update README.md with usage notes

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kdeme 2019-10-30 12:58:10 +01:00 committed by zah
parent cfdab7614d
commit 775ce5ca89
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@ -17,6 +17,7 @@ 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:
@ -25,3 +26,26 @@ To build statically linked versions:
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