Sorry, I can't give your the answer.
You can read the GDB's manual to get the answer yourself. It is like a "memory break point".
Or, You can write a small code to check variable changed or not.
I've read the CodeBlocks Manual but find nothing about watchpoint. But thank you all the same. Maybe C::B cannot do that today. But I think watchpoint is very important when you develope a massive project and facing some bug arising from memory leak.
Since you mentioned GDB's manual, please let me ask some questions, because I'm not familiar with it.
1.Can GDB running at windows platform?
2.I have installed codeblocks-8.02-setup.exe. I think it has contained the GDB Plugins. Am I right? Will I need to find GDB and install it again?
3.I've found a GDB's manual link
http://www.gnu.org/software/gdb/documentation/. Is it right?
4.I've checked every corner of CodeBlocks's interface but found noting about watchpoint. If GDB's manual would help me, does it mean I will debug program through commond line with no GUI?
Thx...