Help understanding structure behaviior in esp now example

[J-M-L]

@gcjr

@J-M-L

When you send the structure, you just send the pointer address and not the content, and obviously the receiver can't do anything with that pointer.

did you mean struct or String?

I was unclear. I obviously meant the value of the pointer to the cstring that is held as part of the String class within the struct

if you have

typedef struct struct_message {
  char a[32];
  int b;
  float c;
  String d;
  bool e;
} struct_message;

d is a String instance (on a UNO sizeof(String) is 6)

the memory representation is something like this (assuming packed)

and so the first entry is actually a pointer (the address of some other region in memory) to the Heap where the data actually lives.

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@rick3939

It did send the actual string data, not a pointer, up until 11 chars was too much. Then nothing in the string.

There was something else at play that tricked you into believing it was working.