Createpen Doesn't Create Memory Leaks?
I've Created a Hpen and Selected It with the Following Code: Hpen hPen = Createpen(Ps_Solid, 1, Rgb(0,0,0)); oldPen = (Hpen)Selectobject(Hdc, hPen); After This...
I've created a HPEN and selected it with the following code:
HPEN hPen = CreatePen(PS_SOLID, 1, RGB(0,0,0));
oldPen = (HPEN)SelectObject(hdc, hPen);
After this i'm drawing something and selecting the old Pen:
SelectObject(hdc, oldPen);
To see memory leaks i use:
#define CRTDBG_MAP_ALLOC
#include <crtdbg.h>
/* This in the main function */
_CrtSetDbgFlag ( _CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF );
If i close the application no mem leak will be shown. But i thought if i don't delete the object with DeleteObject() i get memory leaks.
I've tested the flag with this and it worked:
int* leak = new int;
So there can't be a problem with the flag. Can you help me with this problem or tell me more about why no mem leak is shown?
Thank you!
2 Answers
CreatePen is a win32 api function that (potentially) allocates some memory inside the windows kernel to be used while drawing. The memory allocated with new / new[] is allocated by the C Run-Time Library so it will be catch by the CRT debug functions. They were specifically created to catch memory leaks allocated with malloc / new / new[]
As others have stated, you will not be able to track down GDI leaks this way.
I personally use GDIView for this purpose and am satisfied with it ( if others can recommend other tools for tracking down GDI leaks I would appreciate it ).
Also, you will need to delete the pen after you finish using it ( DeleteObject(hPen) ).
Best regards.
Marcus Vance is a cybersecurity auditor and technology writer dedicated to educating the public about online safety, data privacy regulations, enterprise security, and emerging cyber threats.
