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Apr 28, 2020

Question for the C heads here. Is there a more elegant approach to parsing and creating messages of a specific format without doing a bunch of super error prone math / manual byte fiddling in an array? /1

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Should be able to cast to struct pointers to simplify. Just make sure C stores your struct in memory as you expect. You can also switch on message type to handle specific message types, cast further, etc. If I understand the problem correctly.

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"make sure C stores your struct in memory as you expect" is where my issue is. Is that possible at all? The internet seems to say no when I google about

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You could maybe use the ‘packed’ GCC attribute to ensure you’re struct is stored correctly

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I've stumbled upon this right now. I feel a bit uneasy about it as that seems non-standard and I have no control over the compiler being used by the user. Having it portable would be important.

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I've been using macro composition for this. This might be a bit dense of an explanation, but define your struct as a macro #define MY_STRUCT(field) field(name1,type1) field(name2,type2) and then create a macro SERIALIZE that you can instantiate as MY_STRUCT(SERIALIZE).

12:50 AM · Apr 29, 2020Twitter Web App

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You can the define a macro STRUCT that creates the C struct when you do MY_STRUCT(STRUCT). It's a straightforward way to get "type class instances" in C.

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Tired and didn't try to compile it, but here is the idea boiled down: zwizwa.be/-/c/20200428-2