Looking at Getting the offset of a member in a struct, I realized that you can also use the same technique to get the size of a member of a struct or a union without declaring a variable of that struct. Suppose a struct has been defined as follows:

struct person
{
	int id;
	char name [50];
	double salary;
};

You cannot do sizeof(person->name) or sizeof((struct person).name). But, you can do sizeof(((struct person *) 0)->name).

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