Resolved: When to use calloc or malloc in C

Question:

person* new_person(){
    struct _person* person = calloc(1, sizeof(person));
    person->name = NULL;
    person->child = NULL; 
    return person;
}

person* new_person(){
    struct _person* person = malloc(sizeof(person));
    person->name = NULL;
    person->child = NULL;
    return person;
}

typedef struct _person{
    *void name;
    struct _person* child;
}person;

Answer:

• *void name; is a syntax error.

• Neither struct _person* person = calloc(1, sizeof(person)); nor struct _person* person = malloc(sizeof(person)); will allocate the correct amount of memory because sizeof(person) will evaluate to the size of the pointer person in the definition, not the type person defined as a typedef for struct _person.

    struct _person *person = calloc(1, sizeof(*person));

• the size of the element and the number of elements are separate, thus avoiding silly mistakes in the overall size computation.
• the memory is initialized to all bits zero, which is the zero value of all scalar types on modern systems. This may allow you to simplify the code by omitting explicit initialization of integers and will force initialization to 0 of all extra members added to the structure definition for which the allocation functions might be missing initializers.
• for large arrays, calloc() is actually faster than malloc(size) + memset(s, 0, size), as is documented this answer: https://stackoverflow.com/a/18251590/4593267

If you have better answer, please add a comment about this, thank you!