The task is to create an array with different types of variables, the number of elements is not known in advance. I'm trying to help memcpy create an array with different data types, like this:
char * packet; float a=1.56; int b=5; memcpy(packet,&a,4); memcpy(packet,&b,4); But the segmentation fault error occurs. Tell me please, is it actually implemented in such a way, or am I trying to do something wrong?
char *packet; /* ... */ memcpy(packet,&a,4); You declared a pointer, but did not allocate the memory it points to.
Or:
char packet[4]; // или сколько вам надо or:
char *packet = new char[4]; // или сколько вам надо PS Do you C++ need C++ in this case?
C this is realloc (do not make a classic mistake with the loss of a pointer if realloc() returns NULL ), for C++ is new / memcpy() / delete . - PinkTuxYou make a mistake, and fundamentally wrong :)
You have already indicated the error - you did not allocate memory, and you are trying to write where it is not clear.
But after you write to the allocated memory - what do you want to do with this next? Why this torment? After all, you need somewhere separately to store information like:
Элемент 0 Смещение 0 тип double Элемент 1 Смещение 8 тип char Элемент 2 Смещение 9 тип int All this is good only for POD - that is, roughly speaking, the types of good old C, but not C ++. Question: in the name of what are these torments?
Formulate your most important task - perhaps it can be solved much easier ...
Source: https://ru.stackoverflow.com/questions/589313/
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boost::any. If there is any hierarchy of stored types, then (smart) pointers can be used. All this as a type forstd::vector, for example. True, I suspect that it will be difficult for you at the moment. - αλεχολυτ