pointer to preallocated memory as an input parameter and have the function fill it
- by djones2010
test code:
void modify_it(char * mystuff)
{
char test[7] = "123456"; //last element is null i presume for c style strings here.
//static char test[] = "123123"; //when i do this i thought i should be able to gain access to this bit of memory when the function is destroyed but that does not seem to be the case.
//char * test = new char[7]; //this is also creating memory on stack and not the heap i reckon and gets destroyed once the function is done with.
strcpy_s(mystuff,7,test); //this does the job as long as memory for mystuff has been allocated outside the function.
mystuff = test; //this does not work. I know with c style strings you can't just do string assignments they have to be actually copied. in this case I was using this in conjunction with static char test thinking by having it as static the memory would not get destroyed and i can then simply point mystuff to test and be done with it. i would later have address the memory cleanup in the main function. but anyway this never worked.
}
int main(void)
{
char * mystuff = new char [7]; //allocate memory on heap where the pointer will point
cool(mystuff);
std::string test_case(mystuff);
std::cout<<test_case.c_str(); //this is the only way i know how to use cout by making it into a string c++ string.
delete [] mystuff;
return 0;
}
in the case, of a static array in the function why would it not work.
in the case, when i allocated memory using new in the function does it get created on the stack or heap?
in the case, i have string which needs to be copied into a char * form. everything i see usually requires const char* instead of just char*.
I know i could use reference to take care of this easy. Or char ** to send in the pointer and do it that way. But i just wanted to know if I could do it with just char *. Anyway your thoughts and comments plus any examples would be very helpful.
