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Can Realloc be used without malloc?
malloc is not required, you can use realloc only. malloc(n) is equivalent to realloc(NULL, n) . However, it is often clearer to use malloc instead of special semantics of realloc . It’s not a matter of what works, but not confusing people reading the code.
What happens if you free without malloc?
To do that free() usually has to look-up the originally allocated size of the pointer and if it wasn’t set up by malloc() that process usually corrupts the free-store – resulting in eventual calamitous failure.
Does char * need malloc?
As was indicated by others, you don’t need to use malloc just to do: const char *foo = “bar”; The reason for that is exactly that *foo is a pointer — when you initialize foo you’re not creating a copy of the string, just a pointer to where “bar” lives in the data section of your executable.
Does realloc return the same address?
If realloc() fails the original block is left untouched; it is not freed or moved. Since realloc may move the allocated memory to a new location, you need to account for this. Don’t count on it staying at the same address. The system is allowed to move the whole affair to a different address for whatever reason.
What happens if malloc fails?
If the malloc function is unable to allocate the memory buffer, it returns NULL. ‘If the malloc function failed to allocate memory, it is unlikely that my program will continue to function properly. Most likely, memory will not be enough for other operations, so I cannot bother about the memory allocation errors.
What is the return type of malloc () and calloc ()?
The malloc() and calloc() functions return a pointer to the allocated memory, which is suitably aligned for any built-in type. On error, these functions return NULL. NULL may also be returned by a successful call to malloc() with a size of zero, or by a successful call to calloc() with nmemb or size equal to zero.