Char array size when using certain library functions -

when using library functions (e.g. strftime(), strcpy(), multibytetowidechar()) deal character arrays (instead of std::string's) 1 has 2 options:

• use fixed size array (e.g. char buffer[256];) bad because of string length limit

• use new allocate required size bad when 1 wants create utility function this:

  char * fun(void) {     char * array = new char[exact_required_size];     some_function(array);     return array; } 

  because user of such function has delete array.

and 2nd option isn't possible if 1 can't know exact array size/length before using problematic function (when 1 can't predict how long string function return).

the perfect way use std::string since has variable length , destructor takes care of deallocating memory many library functions don't support std::string (whether should question).

ok, what's problem? - how should use these functions? use fixed size array or use new , make user of function worry deallocating memory? or maybe there is smooth solution didn't think of?

you can use std::string's data() method pointer character array same sequence of characters contained in string object. character pointer returned points constant, non-modifiable character array located somewhere in internal memory. don't need worry deallocating memory referenced pointer string object's destructor automatically.

but original question: depends on how want function work. if you're modifying character array create within function, sounds you'll need allocate memory on heap , return pointer it. user have deallocate memory - there plenty of standard library functions work way.

alternatively, force user pass in character pointer parameter, ensure they've created array , know need deallocate memory themselves. method used more , preferable.