Cast a struct member in GDB Pretty Print?

I want to pretty print this struct struct MyStruct { char buffer[16]; }. Depending on buffer[15] I want to print buffer as a 10 byte string or treat it as a pointer. The 10 byte case is simple and works return self.val['buffer'].string(length = 10)

The second case I can't figure out. I want to do something like (*(char**)buffer[0]). I'm not sure how to do that. I was thinking parse_and_eval could be easy even if its not optimal but I couldn't figure out how to access buffer. I also need to cast the buffer to a 32bit int (len = *(int*)(bufer+4);) I couldn't figure that out either.

If I interpret your description correctly, I think your data is actually layed out like this:

struct MyStruct {
    union {
        char string[10];
        struct {
            char *p;
            int size;
        } ptr;
    }
    int flag;
}

So I think casting the buffer to a pointer of that type, and then choosing the format based on mystruct->flag would make life easier for you.

Even if my interpretation is not correct, try to find the correct version of that struct that captures the duality of the data.