Others have answered how malloc(0) works. I will answer one of the questions that you asked that hasn’t been answered yet (I think). The question is about realloc(malloc(0), 0): What does malloc(0) return? Would the answer be same for realloc(malloc(0),0)? The standard says this about realloc(ptr, size): if ptr is NULL, it behaves like malloc(size), … Read more
When std::vector<T> runs out of capacity it has to allocate a new block. You have correctly covered the reasons. IMO it would make sense to augment the allocator interface. Two of us tried to for C++11 and we were unable to gain support for it: [1] [2] I became convinced that in order to make … Read more
Use ::std::vector! Type* t = (Type*)malloc(sizeof(Type)*n) memset(t, 0, sizeof(Type)*m) becomes ::std::vector<Type> t(n, 0); Then t = (Type*)realloc(t, sizeof(Type) * n2); becomes t.resize(n2); If you want to pass pointer into function, instead of Foo(t) use Foo(&t[0]) It is absolutely correct C++ code, because vector is a smart C-array.