how to free malloc inside failed realloc

问题

I have this struct:

typedef struct person_st{
   char *first_name, *last_name;
   int id;
   Date birthday;  
}*pPerson, Person;

lets say i reallocate sizeof(Person)*(++n) few times. inside each struct i also allocate space for the first_name and last_name.

assuming that at some point there will be allocation failure while i use realloc, what is the safest/smartest way to handle all the first_name and last_name allocations? its there still a way to free them after the realloctaion failure of the Person struct?

thanks.

回答1:

a failed realloc will not disturb the original data , so you can still refer to the old data (always assuming you kept the old pointer given that the failed realloc will return null)

回答2:

the best way to call realloc is something like this:

more_people = realloc(people, count * sizeof(Person));
if (!more_people) {
    // handle failure
} else {
    people = more_people;
}

This way you check the return code from realloc and safely handle the failure

来源：https://stackoverflow.com/questions/42079285/how-to-free-malloc-inside-failed-realloc