Allocating memory on initialisation is a bit questionable. It's better to alloc no memory and let the growth logic handle that case (either by checking for zero

Allocating memory on initialisation is a bit questionable. It's better to alloc no memory and let the growth logic handle that case (either by checking for zero or by including an offset, such as vec->capacity += vec->capacity + 2). The reason is code like this: vector vec; vector_init(&vec); for (i = 0; i < n; i++) vector_append(vec, some_operation(n)); whole_vector_operation(&vec); vector_free(&vec); It's both natural and desirable for this code to do no allocation when n = 0. Since this is C, you might also include a macro to allow for static initialisation: #define VECTOR_INIT { 0, NULL, NULL } or something.