On Sep 4, 6:05 pm, red floyd <no.s...@here.dude> wrote:
ds wrote:
Hi all,
I have to pass an array of doubles to a legacy C function that copies
some data using memcpy. The code would look like this:
extern "C"{
void legacyCFunctionFill(void* arg);
}
...
int number=5;
double *my_array=(double*)calloc(number,sizeof(double));
legacyCFunctionFill((void*)my_array);
// Do sth useful
free(my_array);
The question is: if I change calloc() and free() with new and delete
[] will there be any issues, including portability issues? At first it
seems that it works, having tested that in my program. But I am not
sure if the memory allocated by calloc is the same and can be used the
same way as the memory allocated with new, especially on windows,
Linux and Sun.
Assuming that legacyCFunctionFill() doesn't overrun the buffer (how
*does* it know how much space to fill?), it's fine to use
new[]/delete[]. A pointer is a pointer.
double *my_array = new double[number];
legacyCFunctionFill(my_array); // no cast to void* needed
delete[] my_array; // note use of delete[]
Alternatively:
std::vector<double> myvec(number);
legacyCFunctionFill(&myvec[0]);
// no deletion necessary
Hi floyd,
it is clear that number has to be passed to the legacy function, which
performs a memcpy - no allocation/deallocation on the passed array.
Are you sure that std::vector allocates a continuous block? That would
be a nice solution for what I want to do, but I am afraid that not
all std::vector implementations allocate continuous memory....