Question

Does the following code contain a memory leak of the first three characters in the string?

char * str = (char*)malloc(21 * sizeof(char));
strcpy(str, "01234567890123456879");
str = str + 3;
free(str);

Thanks.

Answer 1

Its worse than a leak, you are not supposed to call free with a pointer not returned from malloc (or realloc/calloc). You could get a leak, or a crash, or who knows what else… What you do is undefined behavior.