malloc - In C, free half of the memory chunk, without freeing the other half -

if have allocated memory chunk

char *a =(char*)malloc(sizeof(char)*10);    

and

strcpy( "string of len 5",a);    

then there way free left on part of memory chunk?
in other scenario if

strcpy("string of len5", (a+5)); 

then first half empty. there way free() first part without deallocating second half?

please don't suggest realloc() allocates new chunk of memory copy content there , release previous.(akaik).

no, there no way can free() half or part of dynamically allocated memory. need free() all @ time.

while getting memory through dynamic memory allocation, pointer. need pass exact pointer free(). passing pointer free() not returned malloc() or family, undefined behaviour.

fyi, see related answer.