another malloc question

if I do this

char * p = (char*) malloc(sizeof(char) * 30);

p[20] = '\0';

free(p);


How much memory did I free? was it the whole 30 bytes that I putted asside with the first statement, or just 21bytes caused by putting a binary 0 at offset 20?

and if it is only 21 bytes, did i just created a memory leak?

You freed 30 bytes.

yes it frees 30 bytes of memory
'\0' is not a specifier for end memory location
it is only a value stored at memory location
it is use a specifier in C for end of string like $ symbol use in Assembly

thanks guys, specialy for the clarifing explanation.