Re: Preventing memory and resource leaks with GDI Objects ???

"Joseph M. Newcomer" <newcomer@flounder.com> wrote in
message news:k397q5ph2r73h9e7lcsjoe0sp3d00ofb9d@4ax.com...


OK so your code is better because it handles a possible
error condition. It may still be wrong though. It looks like
it selects the font, even there was an error in creating
this font. In the case where there is an error creating the
font, I want to keep the original font. So I am guessing
that wrapping the last three lines with an else from the if
statement would fix this.


I keep most of my code in header files that won't compile if
I don't use the inline keyword. This is one aspect the way
that I beat MS VC++ 6.0 and Borland C++ Builder std::string
by a fifty-fold faster performance. I think there was even
one benchmark where I beat Borland by 125-fold.


There is a pointer to something otherwise DeleteObject()
would have nothing to work with. This member function is
available from the CFont object's interface.

I wanted to avoid the sort of memory leak error shown in the
code below. If you create an object using the same pointer
where another object resides, you lose the capability to
remove the original object. It looks like your corrected
code above still has this same problem, depending on how
Windows/Win32/MFC works under the covers. The CFont object
is created in the same location where the old CFont object
is later deleted.

'#include <stdio.h>
#include <malloc.h>

int main() { // Intentioanal Memory Leak
  int* X;
  int Z;
  X = (int*)malloc(104857600);
  for (int N = 0; N < (104857600 / 4); N++)
    *(X + N) = N;
  printf("Hit Return");
  scanf("%c",&Z); // System reports 10 MB allocated

  X = (int*)malloc(104857600); // memory leak
  for (int N = 0; N < (104857600 / 4); N++)
    *(X + N) = N;
  printf("Hit Return");
  scanf("%c",&Z); // System reports 20 MB allocated

  free(X);
  printf("Hit Return");
  scanf("%c",&Z); // System still reports 10 MB
allocated
  return 0; // because of memory leak
}