How can I get the size of a memory block allocated using malloc()? [duplicate]-Collection of common programming errors

Partial solution: on Windows you can use the PageHeap to catch a memory access outside the allocated block.

PageHeap is an alternate memory manager present in the Windows kernel (in the NT varieties but nobody should be using any other version nowadays). It takes every allocation in a process and returns a memory block that has its end aligned with the end of a memory page, then it makes the following page unaccessible (no read, no write access). If the program tries to read or write past the end of the block, you’ll get an access violation you can catch with your favorite debugger.

How to get it: Download and install the package Debugging Tools for Windows from Microsoft: http://www.microsoft.com/whdc/devtools/debugging/default.mspx

then launch the GFlags utility, go to the 3rd tab and enter the name of your executable, then Hit the key. Check the PageHeap checkbox, click OK and you’re good to go.

The last thing: when you’re done with debugging, don’t ever forget to launch GFlags again, and disable PageHeap for the application. GFlags enters this setting into the Registry (under HKLM\Software\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\), so it is persistent, even across reboots.

Also, be aware that using PageHeap can increase the memory needs of your application tremendously.