How to delete a pointer after returning its value inside a function

Question

I have this function:

char* ReadBlock(fstream& stream, int size) {     char* memblock;     memblock = new char[size];     stream.read(memblock, size);     return(memblock); } 

The function is called every time I have to read bytes from a file. I think it allocates new memory every time I use it but how can I free the memory once I have processed the data inside the array? Can I do it from outside the function? Processing data by allocating big blocks gives better performance than allocating and deleting small blocks of data?

Thank you very much for your help!

Answer 1

Dynamic arrays are freed using delete[]:

char* block = ReadBlock(...); // ... do stuff delete[] block; 

Ideally however you don't use manual memory management here:

std::vector<char> ReadBlock(std::fstream& stream, int size) {     std::vector<char> memblock(size);     stream.read(&memblock[0], size);     return memblock; } 

Answer 2

Just delete[] the return value from this function when you've finished with it. It doesn't matter that you're deleting it from outside. Just don't delete it before you finish using it.