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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!
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delete and free() in C++ In C++, the delete operator should only be used either for the pointers pointing to the memory allocated using new operator or for a NULL pointer, and free() should only be used either for the pointers pointing to the memory allocated using malloc() or for a NULL pointer.
We can pass pointers to the function as well as return pointer from a function. But it is not recommended to return the address of a local variable outside the function as it goes out of scope after function returns.
The only thing that ever gets deleted is the object *test , which is identical to the object *test2 (since the pointers are the same), and so you must only delete it once.
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; } 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.
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